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Database: UniProt
Entry: P60033
LinkDB: P60033
Original site: P60033 
ID   CD81_HUMAN              Reviewed;         236 AA.
AC   P60033; P18582; Q5U0J6;
DT   21-NOV-2003, integrated into UniProtKB/Swiss-Prot.
DT   21-NOV-2003, sequence version 1.
DT   29-SEP-2021, entry version 173.
DE   RecName: Full=CD81 antigen;
DE   AltName: Full=26 kDa cell surface protein TAPA-1 {ECO:0000303|PubMed:1695320};
DE   AltName: Full=Target of the antiproliferative antibody 1 {ECO:0000303|PubMed:1695320};
DE   AltName: Full=Tetraspanin-28;
DE            Short=Tspan-28;
DE   AltName: CD_antigen=CD81 {ECO:0000303|PubMed:8766544};
GN   Name=CD81 {ECO:0000303|PubMed:8766544, ECO:0000312|HGNC:HGNC:1701};
GN   Synonyms=TAPA1 {ECO:0000303|PubMed:1695320}, TSPAN28;
OS   Homo sapiens (Human).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae;
OC   Homo.
OX   NCBI_TaxID=9606;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], AND SUBCELLULAR LOCATION.
RX   PubMed=1695320; DOI=10.1128/mcb.10.8.4007-4015.1990;
RA   Oren R., Takahashi S., Doss C., Levy R., Levy S.;
RT   "TAPA-1, the target of an antiproliferative antibody, defines a new family
RT   of transmembrane proteins.";
RL   Mol. Cell. Biol. 10:4007-4015(1990).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RA   Kalnine N., Chen X., Rolfs A., Halleck A., Hines L., Eisenstein S.,
RA   Koundinya M., Raphael J., Moreira D., Kelley T., LaBaer J., Lin Y.,
RA   Phelan M., Farmer A.;
RT   "Cloning of human full-length CDSs in BD Creator(TM) system donor vector.";
RL   Submitted (OCT-2004) to the EMBL/GenBank/DDBJ databases.
RN   [3]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RA   Livingston R.J., Shaffer T., McFarland I., Nguyen C.P., Stanaway I.B.,
RA   Rajkumar N., Johnson E.J., da Ponte S.H., Willa H., Ahearn M.O.,
RA   Bertucci C., Acklestad J., Carroll A., Swanson J., Gildersleeve H.I.,
RA   Nickerson D.A.;
RL   Submitted (OCT-2006) to the EMBL/GenBank/DDBJ databases.
RN   [4]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX   PubMed=16554811; DOI=10.1038/nature04632;
RA   Taylor T.D., Noguchi H., Totoki Y., Toyoda A., Kuroki Y., Dewar K.,
RA   Lloyd C., Itoh T., Takeda T., Kim D.-W., She X., Barlow K.F., Bloom T.,
RA   Bruford E., Chang J.L., Cuomo C.A., Eichler E., FitzGerald M.G.,
RA   Jaffe D.B., LaButti K., Nicol R., Park H.-S., Seaman C., Sougnez C.,
RA   Yang X., Zimmer A.R., Zody M.C., Birren B.W., Nusbaum C., Fujiyama A.,
RA   Hattori M., Rogers J., Lander E.S., Sakaki Y.;
RT   "Human chromosome 11 DNA sequence and analysis including novel gene
RT   identification.";
RL   Nature 440:497-500(2006).
RN   [5]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC   TISSUE=Brain;
RX   PubMed=15489334; DOI=10.1101/gr.2596504;
RG   The MGC Project Team;
RT   "The status, quality, and expansion of the NIH full-length cDNA project:
RT   the Mammalian Gene Collection (MGC).";
RL   Genome Res. 14:2121-2127(2004).
RN   [6]
RP   INTERACTION WITH IFITM1, AND SUBCELLULAR LOCATION.
RX   PubMed=2398277;
RA   Takahashi S., Doss C., Levy S., Levy R.;
RT   "TAPA-1, the target of an antiproliferative antibody, is associated on the
RT   cell surface with the Leu-13 antigen.";
RL   J. Immunol. 145:2207-2213(1990).
RN   [7]
RP   TOPOLOGY.
RX   PubMed=1860863;
RA   Levy S., Nguyen V.Q., Andria M.L., Takahashi S.;
RT   "Structure and membrane topology of TAPA-1.";
RL   J. Biol. Chem. 266:14597-14602(1991).
RN   [8]
RP   IDENTIFICATION IN A COMPLEX WITH CR2; CD19 AND IFITM1, AND SUBCELLULAR
RP   LOCATION.
RX   PubMed=1383329;
RA   Bradbury L.E., Kansas G.S., Levy S., Evans R.L., Tedder T.F.;
RT   "The CD19/CD21 signal transducing complex of human B lymphocytes includes
RT   the target of antiproliferative antibody-1 and Leu-13 molecules.";
RL   J. Immunol. 149:2841-2850(1992).
RN   [9]
RP   FUNCTION, INTERACTION WITH IFITM1, AND INTERACTION WITH HLA-DR.
RX   PubMed=8409388;
RA   Schick M.R., Levy S.;
RT   "The TAPA-1 molecule is associated on the surface of B cells with HLA-DR
RT   molecules.";
RL   J. Immunol. 151:4090-4097(1993).
RN   [10]
RP   FUNCTION.
RX   PubMed=8766544; DOI=10.1002/eji.1830260706;
RA   Secrist H., Levy S., DeKruyff R.H., Umetsu D.T.;
RT   "Ligation of TAPA-1 (CD81) or major histocompatibility complex class II in
RT   co-cultures of human B and T lymphocytes enhances interleukin-4 synthesis
RT   by antigen-specific CD4+ T cells.";
RL   Eur. J. Immunol. 26:1435-1442(1996).
RN   [11]
RP   INTERACTION WITH IGSF8.
RX   PubMed=11504738; DOI=10.1074/jbc.m107338200;
RA   Stipp C.S., Kolesnikova T.V., Hemler M.E.;
RT   "EWI-2 is a major CD9 and CD81 partner and member of a novel Ig protein
RT   subfamily.";
RL   J. Biol. Chem. 276:40545-40554(2001).
RN   [12]
RP   INTERACTION WITH HCV E1/E2 ENVELOPE HETERODIMER (MICROBIAL INFECTION).
RX   PubMed=12913001; DOI=10.1074/jbc.m305289200;
RA   Bartosch B., Vitelli A., Granier C., Goujon C., Dubuisson J., Pascale S.,
RA   Scarselli E., Cortese R., Nicosia A., Cosset F.-L.;
RT   "Cell entry of hepatitis C virus requires a set of co-receptors that
RT   include the CD81 tetraspanin and the SR-B1 scavenger receptor.";
RL   J. Biol. Chem. 278:41624-41630(2003).
RN   [13]
RP   FUNCTION, TISSUE SPECIFICITY, AND INTERACTION WITH CD9.
RX   PubMed=12796480; DOI=10.1083/jcb.200212031;
RA   Takeda Y., Tachibana I., Miyado K., Kobayashi M., Miyazaki T.,
RA   Funakoshi T., Kimura H., Yamane H., Saito Y., Goto H., Yoneda T.,
RA   Yoshida M., Kumagai T., Osaki T., Hayashi S., Kawase I., Mekada E.;
RT   "Tetraspanins CD9 and CD81 function to prevent the fusion of mononuclear
RT   phagocytes.";
RL   J. Cell Biol. 161:945-956(2003).
RN   [14]
RP   INTERACTION WITH HCV E1/E2 ENVELOPE HETERODIMER (MICROBIAL INFECTION).
RX   PubMed=12970454; DOI=10.1128/jvi.77.19.10677-10683.2003;
RA   Cocquerel L., Kuo C.-C., Dubuisson J., Levy S.;
RT   "CD81-dependent binding of hepatitis C virus E1E2 heterodimers.";
RL   J. Virol. 77:10677-10683(2003).
RN   [15]
RP   FUNCTION (MICROBIAL INFECTION), AND TISSUE SPECIFICITY.
RX   PubMed=12483205; DOI=10.1038/nm808;
RA   Silvie O., Rubinstein E., Franetich J.F., Prenant M., Belnoue E., Renia L.,
RA   Hannoun L., Eling W., Levy S., Boucheix C., Mazier D.;
RT   "Hepatocyte CD81 is required for Plasmodium falciparum and Plasmodium
RT   yoelii sporozoite infectivity.";
RL   Nat. Med. 9:93-96(2003).
RN   [16]
RP   PTM, AND FUNCTION.
RX   PubMed=15161911; DOI=10.1074/jbc.m404410200;
RA   Cherukuri A., Carter R.H., Brooks S., Bornmann W., Finn R., Dowd C.S.,
RA   Pierce S.K.;
RT   "B cell signaling is regulated by induced palmitoylation of CD81.";
RL   J. Biol. Chem. 279:31973-31982(2004).
RN   [17]
RP   INTERACTION WITH ADGRG1 AND GNA11.
RX   PubMed=15004227; DOI=10.1091/mbc.e03-12-0886;
RA   Little K.D., Hemler M.E., Stipp C.S.;
RT   "Dynamic regulation of a GPCR-tetraspanin-G protein complex on intact
RT   cells: central role of CD81 in facilitating GPR56-Galpha q/11
RT   association.";
RL   Mol. Biol. Cell 15:2375-2387(2004).
RN   [18]
RP   FUNCTION, AND INTERACTION WITH CD19.
RX   PubMed=16449649; DOI=10.1128/mcb.26.4.1373-1385.2006;
RA   Shoham T., Rajapaksa R., Kuo C.C., Haimovich J., Levy S.;
RT   "Building of the tetraspanin web: distinct structural domains of CD81
RT   function in different cellular compartments.";
RL   Mol. Cell. Biol. 26:1373-1385(2006).
RN   [19]
RP   FUNCTION (MICROBIAL INFECTION), SUBUNIT, SUBCELLULAR LOCATION, AND
RP   INTERACTION WITH CLDN1; CLDN6 AND CLDN9.
RX   PubMed=20375010; DOI=10.1074/jbc.m110.104836;
RA   Harris H.J., Davis C., Mullins J.G., Hu K., Goodall M., Farquhar M.J.,
RA   Mee C.J., McCaffrey K., Young S., Drummer H., Balfe P., McKeating J.A.;
RT   "Claudin association with CD81 defines hepatitis C virus entry.";
RL   J. Biol. Chem. 285:21092-21102(2010).
RN   [20]
RP   INVOLVEMENT IN CVID6, FUNCTION, SUBCELLULAR LOCATION, AND TISSUE
RP   SPECIFICITY.
RX   PubMed=20237408; DOI=10.1172/jci39748;
RA   van Zelm M.C., Smet J., Adams B., Mascart F., Schandene L., Janssen F.,
RA   Ferster A., Kuo C.-C., Levy S., van Dongen J.J.M., van der Burg M.;
RT   "CD81 gene defect in humans disrupts CD19 complex formation and leads to
RT   antibody deficiency.";
RL   J. Clin. Invest. 120:1265-1274(2010).
RN   [21]
RP   IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
RX   PubMed=21269460; DOI=10.1186/1752-0509-5-17;
RA   Burkard T.R., Planyavsky M., Kaupe I., Breitwieser F.P., Buerckstuemmer T.,
RA   Bennett K.L., Superti-Furga G., Colinge J.;
RT   "Initial characterization of the human central proteome.";
RL   BMC Syst. Biol. 5:17-17(2011).
RN   [22]
RP   INTERACTION WITH CD53 AND SCIMP.
RX   PubMed=21930792; DOI=10.1128/mcb.05817-11;
RA   Draber P., Vonkova I., Stepanek O., Hrdinka M., Kucova M., Skopcova T.,
RA   Otahal P., Angelisova P., Horejsi V., Yeung M., Weiss A., Brdicka T.;
RT   "SCIMP, a transmembrane adapter protein involved in major
RT   histocompatibility complex class II signaling.";
RL   Mol. Cell. Biol. 31:4550-4562(2011).
RN   [23]
RP   FUNCTION (MICROBIAL INFECTION), AND INTERACTION WITH CLDN1.
RX   PubMed=21516087; DOI=10.1038/nm.2341;
RA   Lupberger J., Zeisel M.B., Xiao F., Thumann C., Fofana I., Zona L.,
RA   Davis C., Mee C.J., Turek M., Gorke S., Royer C., Fischer B., Zahid M.N.,
RA   Lavillette D., Fresquet J., Cosset F.L., Rothenberg S.M., Pietschmann T.,
RA   Patel A.H., Pessaux P., Doffoel M., Raffelsberger W., Poch O.,
RA   McKeating J.A., Brino L., Baumert T.F.;
RT   "EGFR and EphA2 are host factors for hepatitis C virus entry and possible
RT   targets for antiviral therapy.";
RL   Nat. Med. 17:589-595(2011).
RN   [24]
RP   FUNCTION, TISSUE SPECIFICITY, AND SUBCELLULAR LOCATION.
RX   PubMed=22307619; DOI=10.1073/pnas.1121307109;
RA   Sagi Y., Landrigan A., Levy R., Levy S.;
RT   "Complementary costimulation of human T-cell subpopulations by cluster of
RT   differentiation 28 (CD28) and CD81.";
RL   Proc. Natl. Acad. Sci. U.S.A. 109:1613-1618(2012).
RN   [25]
RP   FUNCTION, INTERACTION WITH CD247, INTERACTION WITH ICAM1, AND INTERACTION
RP   WITH CD9.
RX   PubMed=23858057; DOI=10.1128/mcb.00302-13;
RA   Rocha-Perugini V., Zamai M., Gonzalez-Granado J.M., Barreiro O., Tejera E.,
RA   Yanez-Mo M., Caiolfa V.R., Sanchez-Madrid F.;
RT   "CD81 controls sustained T cell activation signaling and defines the
RT   maturation stages of cognate immunological synapses.";
RL   Mol. Cell. Biol. 33:3644-3658(2013).
RN   [26]
RP   FUNCTION, INTERACTION WITH IFITM1, AND SUBCELLULAR LOCATION.
RX   PubMed=26354436; DOI=10.1074/jbc.m115.657346;
RA   Narayana S.K., Helbig K.J., McCartney E.M., Eyre N.S., Bull R.A.,
RA   Eltahla A., Lloyd A.R., Beard M.R.;
RT   "The Interferon-induced Transmembrane Proteins, IFITM1, IFITM2, and IFITM3
RT   Inhibit Hepatitis C Virus Entry.";
RL   J. Biol. Chem. 290:25946-25959(2015).
RN   [27]
RP   INTERACTION WITH INTEGRIN ITGAV:ITGB3, AND MUTAGENESIS OF LYS-116; ILE-119;
RP   LYS-121; LYS-124; PHE-126; LYS-144; LYS-148; PHE-186 AND LYS-187.
RX   PubMed=27993971; DOI=10.1042/bcj20160998;
RA   Yu J., Lee C.Y., Changou C.A., Cedano-Prieto D.M., Takada Y.K., Takada Y.;
RT   "The CD9, CD81, and CD151 EC2 domains bind to the classical RGD-binding
RT   site of integrin alphavbeta3.";
RL   Biochem. J. 474:589-596(2017).
RN   [28]
RP   FUNCTION, FUNCTION (MICROBIAL INFECTION), AND INTERACTION WITH SAMHD1.
RX   PubMed=28871089; DOI=10.1038/s41564-017-0019-0;
RA   Rocha-Perugini V., Suarez H., Alvarez S., Lopez-Martin S., Lenzi G.M.,
RA   Vences-Catalan F., Levy S., Kim B., Munoz-Fernandez M.A.,
RA   Sanchez-Madrid F., Yanez-Mo M.;
RT   "CD81 association with SAMHD1 enhances HIV-1 reverse transcription by
RT   increasing dNTP levels.";
RL   Nat. Microbiol. 2:1513-1522(2017).
RN   [29] {ECO:0007744|PDB:1G8Q}
RP   X-RAY CRYSTALLOGRAPHY (1.6 ANGSTROMS) OF 113-202.
RX   PubMed=11226150; DOI=10.1093/emboj/20.1.12;
RA   Kitadokoro K., Bordo D., Galli G., Petracca R., Falugi F., Abrignani S.,
RA   Grandi G., Bolognesi M.;
RT   "CD81 extracellular domain 3D structure: insight into the tetraspanin
RT   superfamily structural motifs.";
RL   EMBO J. 20:12-18(2001).
RN   [30] {ECO:0007744|PDB:1IV5}
RP   X-RAY CRYSTALLOGRAPHY (2.6 ANGSTROMS) OF 113-201.
RX   PubMed=12437138; DOI=10.1515/bc.2002.164;
RA   Kitadokoro K., Ponassi M., Galli G., Petracca R., Falugi F., Grandi G.,
RA   Bolognesi M.;
RT   "Subunit association and conformational flexibility in the head subdomain
RT   of human CD81 large extracellular loop.";
RL   Biol. Chem. 383:1447-1452(2002).
RN   [31] {ECO:0007744|PDB:3X0E}
RP   X-RAY CRYSTALLOGRAPHY (1.84 ANGSTROMS) OF 113-202, FUNCTION (MICROBIAL
RP   INFECTION), INTERACTION WITH HCV ENVELOPE PROTEIN E2 (MICROBIAL INFECTION),
RP   DISULFIDE BONDS, AND MUTAGENESIS OF GLU-188 AND ASP-196.
RX   PubMed=26116703; DOI=10.1096/fj.15-272880;
RA   Yang W., Zhang M., Chi X., Liu X., Qin B., Cui S.;
RT   "An intramolecular bond at cluster of differentiation 81 ectodomain is
RT   important for hepatitis C virus entry.";
RL   FASEB J. 29:4214-4226(2015).
RN   [32] {ECO:0007744|PDB:5TCX}
RP   X-RAY CRYSTALLOGRAPHY (2.96 ANGSTROMS), FUNCTION, TOPOLOGY, DISULFIDE
RP   BONDS, CHOLESTEROL BINDING, DOMAIN, AND MUTAGENESIS OF GLU-219.
RX   PubMed=27881302; DOI=10.1016/j.cell.2016.09.056;
RA   Zimmerman B., Kelly B., McMillan B.J., Seegar T.C.M., Dror R.O.,
RA   Kruse A.C., Blacklow S.C.;
RT   "Crystal Structure of a Full-Length Human Tetraspanin Reveals a
RT   Cholesterol-Binding Pocket.";
RL   Cell 167:1041-1051.E11(2016).
RN   [33] {ECO:0007744|PDB:5M2C, ECO:0007744|PDB:5M33, ECO:0007744|PDB:5M3D, ECO:0007744|PDB:5M3T, ECO:0007744|PDB:5M4R}
RP   X-RAY CRYSTALLOGRAPHY (1.28 ANGSTROMS) OF 113-201, AND DISULFIDE BONDS.
RX   PubMed=27916518; DOI=10.1016/j.str.2016.11.003;
RA   Cunha E.S., Sfriso P., Rojas A.L., Roversi P., Hospital A., Orozco M.,
RA   Abrescia N.G.A.;
RT   "Mechanism of Structural Tuning of the Hepatitis C Virus Human Cellular
RT   Receptor CD81 Large Extracellular Loop.";
RL   Structure 25:53-65(2017).
CC   -!- FUNCTION: Structural component of specialized membrane microdomains
CC       known as tetraspanin-enriched microdomains (TERMs), which act as
CC       platforms for receptor clustering and signaling. Essential for
CC       trafficking and compartmentalization of CD19 receptor on the surface of
CC       activated B cells (PubMed:20237408, PubMed:27881302, PubMed:16449649).
CC       Upon initial encounter with microbial pathogens, enables the assembly
CC       of CD19-CR2/CD21 and B cell receptor (BCR) complexes at signaling
CC       TERMs, lowering the threshold dose of antigen required to trigger B
CC       cell clonal expansion and antibody production (PubMed:15161911,
CC       PubMed:20237408). In T cells, facilitates the localization of CD247/CD3
CC       zeta at antigen-induced synapses with B cells, providing for
CC       costimulation and polarization toward T helper type 2 phenotype
CC       (PubMed:22307619, PubMed:23858057, PubMed:8766544). Present in MHC
CC       class II compartments, may also play a role in antigen presentation
CC       (PubMed:8409388, PubMed:8766544). Can act both as positive and negative
CC       regulator of homotypic or heterotypic cell-cell fusion processes.
CC       Positively regulates sperm-egg fusion and may be involved in acrosome
CC       reaction (By similarity). In myoblasts, associates with CD9 and PTGFRN
CC       and inhibits myotube fusion during muscle regeneration (By similarity).
CC       In macrophages, associates with CD9 and beta-1 and beta-2 integrins,
CC       and prevents macrophage fusion into multinucleated giant cells
CC       specialized in ingesting complement-opsonized large particles
CC       (PubMed:12796480). Also prevents the fusion of mononuclear cell
CC       progenitors into osteoclasts in charge of bone resorption (By
CC       similarity). May regulate the compartmentalization of enzymatic
CC       activities. In T cells, defines the subcellular localization of dNTPase
CC       SAMHD1 and permits its degradation by the proteasome, thereby
CC       controlling intracellular dNTP levels (PubMed:28871089). Also involved
CC       in cell adhesion and motility. Positively regulates integrin-mediated
CC       adhesion of macrophages, particularly relevant for the inflammatory
CC       response in the lung (By similarity). {ECO:0000250|UniProtKB:P35762,
CC       ECO:0000269|PubMed:12796480, ECO:0000269|PubMed:15161911,
CC       ECO:0000269|PubMed:16449649, ECO:0000269|PubMed:20237408,
CC       ECO:0000269|PubMed:22307619, ECO:0000269|PubMed:23858057,
CC       ECO:0000269|PubMed:27881302, ECO:0000269|PubMed:28871089,
CC       ECO:0000269|PubMed:8409388, ECO:0000269|PubMed:8766544}.
CC   -!- FUNCTION: (Microbial infection) Acts as a receptor for hepatitis C
CC       virus (HCV) in hepatocytes. Association with CLDN1 and the CLDN1-CD81
CC       receptor complex is essential for HCV entry into host cell.
CC       {ECO:0000269|PubMed:20375010, ECO:0000269|PubMed:21516087,
CC       ECO:0000269|PubMed:26116703, ECO:0000269|PubMed:26354436}.
CC   -!- FUNCTION: (Microbial infection) Involved in SAMHD1-dependent
CC       restriction of HIV-1 replication. May support early replication of both
CC       R5- and X4-tropic HIV-1 viruses in T cells, likely via proteasome-
CC       dependent degradation of SAMHD1. {ECO:0000269|PubMed:28871089}.
CC   -!- FUNCTION: (Microbial infection) Specifically required for Plasmodium
CC       falciparum infectivity of hepatocytes, controlling sporozoite entry
CC       into hepatocytes via the parasitophorous vacuole and subsequent
CC       parasite differentiation to exoerythrocytic forms.
CC       {ECO:0000269|PubMed:12483205}.
CC   -!- SUBUNIT: Homodimer (PubMed:20375010). Part of a complex composed of
CC       CD19, CR2/CD21, CD81 and IFITM1/CD225 in the membrane of mature B
CC       cells. Interacts (via the second extracellular domain) with CD19; this
CC       interaction is initiated early during biosynthesis in the ER and
CC       enables trafficking of only properly folded CD19 (PubMed:16449649,
CC       PubMed:1383329). Part of a complex that includes MHC class II/HLA-DR
CC       molecules and IFITM1 (PubMed:8409388). Interacts with IFITM1
CC       (PubMed:2398277, PubMed:26354436). Interacts with IFITM2 and IFITM3 (By
CC       similarity). Part of integrin-tetraspanin complex composed of CD9,
CC       CD81, beta-1 and beta-2 integrins in the membrane of
CC       monocyte/macrophages (PubMed:12796480). Interacts (via the second
CC       extracellular domain) with integrin ITGAV:ITGB3 (PubMed:27993971).
CC       Interacts with CD247/CD3 zeta, ICAM1 and CD9 at the immune synapse on T
CC       cell membrane (PubMed:23858057). Part of a GPCR-tetraspanin complex
CC       consisting at least of ADGRG1, CD81, possibly CD9, and GNA11 in which
CC       CD81 enhances the association of ADGRG1 with GNA11 (PubMed:15004227).
CC       Part of a complex composed of CD9, CD81, PTGFRN and IGSF8 (By
CC       similarity). Interacts directly with IGSF8 (PubMed:11504738). Interacts
CC       with CD53 and SCIMP (PubMed:21930792). Interacts with SAMHD1 (via its
CC       C-terminus) (PubMed:28871089). Interacts with glypican GPC3 and with
CC       the transcriptional repressor HHEX; binding to GPC3 decreases the
CC       availability of free CD81 for binding to HHEX, resulting in nuclear
CC       translocation of HHEX and transcriptional repression (By similarity).
CC       Interacts with CLDN1 (PubMed:20375010, PubMed:21516087). Interacts with
CC       CLDN6 and CLDN9 (PubMed:20375010). {ECO:0000250|UniProtKB:P35762,
CC       ECO:0000269|PubMed:12796480, ECO:0000269|PubMed:1383329,
CC       ECO:0000269|PubMed:16449649, ECO:0000269|PubMed:20375010,
CC       ECO:0000269|PubMed:23858057, ECO:0000269|PubMed:2398277,
CC       ECO:0000269|PubMed:26354436, ECO:0000269|PubMed:28871089,
CC       ECO:0000269|PubMed:8409388}.
CC   -!- SUBUNIT: (Microbial infection) Plays a critical role in HCV attachment
CC       and/or cell entry by interacting with HCV E1/E2 glycoproteins
CC       heterodimer. {ECO:0000269|PubMed:12913001, ECO:0000269|PubMed:12970454,
CC       ECO:0000269|PubMed:26116703}.
CC   -!- INTERACTION:
CC       P60033; O14672: ADAM10; NbExp=9; IntAct=EBI-712921, EBI-1536151;
CC       P60033; PRO_0000029067 [O14672]: ADAM10; NbExp=2; IntAct=EBI-712921, EBI-21222747;
CC       P60033; Q13520: AQP6; NbExp=3; IntAct=EBI-712921, EBI-13059134;
CC       P60033; Q10589: BST2; NbExp=3; IntAct=EBI-712921, EBI-2476339;
CC       P60033; Q7Z7G2: CPLX4; NbExp=3; IntAct=EBI-712921, EBI-18013275;
CC       P60033; Q15125: EBP; NbExp=3; IntAct=EBI-712921, EBI-3915253;
CC       P60033; Q9Y282: ERGIC3; NbExp=3; IntAct=EBI-712921, EBI-781551;
CC       P60033; Q5JX71: FAM209A; NbExp=3; IntAct=EBI-712921, EBI-18304435;
CC       P60033; P35212: GJA4; NbExp=3; IntAct=EBI-712921, EBI-6918707;
CC       P60033; Q5T7V8: GORAB; NbExp=3; IntAct=EBI-712921, EBI-3917143;
CC       P60033; Q8TDT2: GPR152; NbExp=3; IntAct=EBI-712921, EBI-13345167;
CC       P60033; Q8TED1: GPX8; NbExp=3; IntAct=EBI-712921, EBI-11721746;
CC       P60033; Q14739: LBR; NbExp=3; IntAct=EBI-712921, EBI-1055147;
CC       P60033; Q8TAF8: LHFPL5; NbExp=3; IntAct=EBI-712921, EBI-2820517;
CC       P60033; Q96PE7: MCEE; NbExp=3; IntAct=EBI-712921, EBI-10292326;
CC       P60033; Q9Y676: MRPS18B; NbExp=3; IntAct=EBI-712921, EBI-750085;
CC       P60033; O14524-2: NEMP1; NbExp=3; IntAct=EBI-712921, EBI-10969203;
CC       P60033; Q13113: PDZK1IP1; NbExp=3; IntAct=EBI-712921, EBI-716063;
CC       P60033; Q9NR31: SAR1A; NbExp=3; IntAct=EBI-712921, EBI-3920694;
CC       P60033; Q8WTV0: SCARB1; NbExp=4; IntAct=EBI-712921, EBI-78657;
CC       P60033; Q5VUM1: SDHAF4; NbExp=3; IntAct=EBI-712921, EBI-16769525;
CC       P60033; Q9BXS9-3: SLC26A6; NbExp=3; IntAct=EBI-712921, EBI-12814225;
CC       P60033; Q16623: STX1A; NbExp=3; IntAct=EBI-712921, EBI-712466;
CC       P60033; Q8WY91: THAP4; NbExp=3; IntAct=EBI-712921, EBI-726691;
CC       P60033; Q9Y320: TMX2; NbExp=3; IntAct=EBI-712921, EBI-6447886;
CC       P60033; Q9NSU2-1: TREX1; NbExp=3; IntAct=EBI-712921, EBI-16746122;
CC       P60033; PRO_0000037570 [P27958]; Xeno; NbExp=11; IntAct=EBI-712921, EBI-6904269;
CC       P60033; PRO_0000045596 [Q99IB8]; Xeno; NbExp=2; IntAct=EBI-712921, EBI-6901449;
CC   -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:1383329,
CC       ECO:0000269|PubMed:1695320, ECO:0000269|PubMed:20237408,
CC       ECO:0000269|PubMed:22307619, ECO:0000269|PubMed:2398277,
CC       ECO:0000269|PubMed:26354436}; Multi-pass membrane protein
CC       {ECO:0000255}. Basolateral cell membrane {ECO:0000269|PubMed:20375010};
CC       Multi-pass membrane protein {ECO:0000255}. Note=Associates with CLDN1
CC       and the CLDN1-CD81 complex localizes to the basolateral cell membrane.
CC       {ECO:0000269|PubMed:20375010}.
CC   -!- TISSUE SPECIFICITY: Expressed on B cells (at protein level)
CC       (PubMed:20237408). Expressed in hepatocytes (at protein level)
CC       (PubMed:12483205). Expressed in monocytes/macrophages (at protein
CC       level) (PubMed:12796480). Expressed on both naive and memory CD4-
CC       positive T cells (at protein level) (PubMed:22307619).
CC       {ECO:0000269|PubMed:12483205, ECO:0000269|PubMed:12796480,
CC       ECO:0000269|PubMed:20237408, ECO:0000269|PubMed:22307619}.
CC   -!- DOMAIN: Binds cholesterol in a cavity lined by the transmembrane spans.
CC       {ECO:0000269|PubMed:27881302}.
CC   -!- PTM: Not glycosylated. {ECO:0000305}.
CC   -!- PTM: Likely constitutively palmitoylated at low levels. Protein
CC       palmitoylation is up-regulated upon coligation of BCR and CD9-C2R-CD81
CC       complexes in lipid rafts. {ECO:0000269|PubMed:15161911}.
CC   -!- DISEASE: Immunodeficiency, common variable, 6 (CVID6) [MIM:613496]: A
CC       primary immunodeficiency characterized by antibody deficiency,
CC       hypogammaglobulinemia, recurrent bacterial infections and an inability
CC       to mount an antibody response to antigen. The defect results from a
CC       failure of B-cell differentiation and impaired secretion of
CC       immunoglobulins; the numbers of circulating B-cells is usually in the
CC       normal range, but can be low. {ECO:0000269|PubMed:20237408}. Note=The
CC       disease is caused by variants affecting the gene represented in this
CC       entry.
CC   -!- SIMILARITY: Belongs to the tetraspanin (TM4SF) family. {ECO:0000305}.
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DR   EMBL; M33680; AAA36663.1; -; mRNA.
DR   EMBL; BT019507; AAV38314.1; -; mRNA.
DR   EMBL; BT019508; AAV38315.1; -; mRNA.
DR   EMBL; EF064749; ABK41932.1; -; Genomic_DNA.
DR   EMBL; AC129929; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; AC124057; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; BC002978; AAH02978.1; -; mRNA.
DR   EMBL; BC093047; AAH93047.1; -; mRNA.
DR   CCDS; CCDS7734.1; -.
DR   PIR; A35649; A35649.
DR   RefSeq; NP_001284578.1; NM_001297649.1.
DR   RefSeq; NP_004347.1; NM_004356.3.
DR   PDB; 1G8Q; X-ray; 1.60 A; A/B=113-201.
DR   PDB; 1IV5; X-ray; 2.60 A; A/B=113-201.
DR   PDB; 2AVZ; Model; -; A=1-236.
DR   PDB; 3X0E; X-ray; 1.84 A; A/B=113-202.
DR   PDB; 5DFV; X-ray; 2.80 A; A/B=112-201.
DR   PDB; 5DFW; X-ray; 2.33 A; A=112-201.
DR   PDB; 5M2C; X-ray; 1.96 A; A/B=112-201.
DR   PDB; 5M33; X-ray; 1.28 A; A/B=113-201.
DR   PDB; 5M3D; X-ray; 2.38 A; A/B/C/D=112-201.
DR   PDB; 5M3T; X-ray; 2.02 A; A/B=112-201.
DR   PDB; 5M4R; X-ray; 3.10 A; A/B/C/D/E=112-201.
DR   PDB; 5TCX; X-ray; 2.96 A; A=2-236.
DR   PDB; 6EJG; X-ray; 2.82 A; A/B=112-202.
DR   PDB; 6EJM; X-ray; 2.15 A; A/B=112-202.
DR   PDB; 6EK2; X-ray; 2.65 A; A/B=112-201.
DR   PDB; 6U9S; X-ray; 2.40 A; C/F=112-200.
DR   PDB; 7JIC; EM; 3.80 A; B=2-236.
DR   PDBsum; 1G8Q; -.
DR   PDBsum; 1IV5; -.
DR   PDBsum; 2AVZ; -.
DR   PDBsum; 3X0E; -.
DR   PDBsum; 5DFV; -.
DR   PDBsum; 5DFW; -.
DR   PDBsum; 5M2C; -.
DR   PDBsum; 5M33; -.
DR   PDBsum; 5M3D; -.
DR   PDBsum; 5M3T; -.
DR   PDBsum; 5M4R; -.
DR   PDBsum; 5TCX; -.
DR   PDBsum; 6EJG; -.
DR   PDBsum; 6EJM; -.
DR   PDBsum; 6EK2; -.
DR   PDBsum; 6U9S; -.
DR   PDBsum; 7JIC; -.
DR   BMRB; P60033; -.
DR   SMR; P60033; -.
DR   BioGRID; 107413; 279.
DR   CORUM; P60033; -.
DR   IntAct; P60033; 294.
DR   MINT; P60033; -.
DR   STRING; 9606.ENSP00000263645; -.
DR   BindingDB; P60033; -.
DR   ChEMBL; CHEMBL1075180; -.
DR   TCDB; 8.A.40.1.1; the tetraspanin (tetraspanin) family.
DR   GlyGen; P60033; 1 site, 1 O-linked glycan (1 site).
DR   iPTMnet; P60033; -.
DR   PhosphoSitePlus; P60033; -.
DR   SwissPalm; P60033; -.
DR   BioMuta; CD81; -.
DR   DMDM; 38503376; -.
DR   EPD; P60033; -.
DR   jPOST; P60033; -.
DR   MassIVE; P60033; -.
DR   MaxQB; P60033; -.
DR   PaxDb; P60033; -.
DR   PeptideAtlas; P60033; -.
DR   PRIDE; P60033; -.
DR   ProteomicsDB; 57182; -.
DR   ABCD; P60033; 10 sequenced antibodies.
DR   Antibodypedia; 1570; 1299 antibodies.
DR   DNASU; 975; -.
DR   Ensembl; ENST00000263645; ENSP00000263645; ENSG00000110651.
DR   GeneID; 975; -.
DR   KEGG; hsa:975; -.
DR   UCSC; uc001lwf.2; human.
DR   CTD; 975; -.
DR   DisGeNET; 975; -.
DR   GeneCards; CD81; -.
DR   HGNC; HGNC:1701; CD81.
DR   HPA; ENSG00000110651; Low tissue specificity.
DR   MalaCards; CD81; -.
DR   MIM; 186845; gene.
DR   MIM; 613496; phenotype.
DR   neXtProt; NX_P60033; -.
DR   OpenTargets; ENSG00000110651; -.
DR   Orphanet; 1572; Common variable immunodeficiency.
DR   PharmGKB; PA26240; -.
DR   VEuPathDB; HostDB:ENSG00000110651; -.
DR   eggNOG; KOG3882; Eukaryota.
DR   GeneTree; ENSGT00940000158805; -.
DR   HOGENOM; CLU_055524_10_0_1; -.
DR   InParanoid; P60033; -.
DR   OMA; HETLSCC; -.
DR   OrthoDB; 1205716at2759; -.
DR   PhylomeDB; P60033; -.
DR   TreeFam; TF352895; -.
DR   PathwayCommons; P60033; -.
DR   Reactome; R-HSA-198933; Immunoregulatory interactions between a Lymphoid and a non-Lymphoid cell.
DR   Reactome; R-HSA-977606; Regulation of Complement cascade.
DR   SignaLink; P60033; -.
DR   BioGRID-ORCS; 975; 16 hits in 1018 CRISPR screens.
DR   ChiTaRS; CD81; human.
DR   EvolutionaryTrace; P60033; -.
DR   GeneWiki; CD81; -.
DR   GenomeRNAi; 975; -.
DR   Pharos; P60033; Tchem.
DR   PRO; PR:P60033; -.
DR   Proteomes; UP000005640; Chromosome 11.
DR   RNAct; P60033; protein.
DR   Bgee; ENSG00000110651; Expressed in stromal cell of endometrium and 244 other tissues.
DR   ExpressionAtlas; P60033; baseline and differential.
DR   Genevisible; P60033; HS.
DR   GO; GO:0009925; C:basal plasma membrane; IDA:ARUK-UCL.
DR   GO; GO:0016323; C:basolateral plasma membrane; IDA:UniProtKB.
DR   GO; GO:0070062; C:extracellular exosome; IDA:UniProtKB.
DR   GO; GO:0005925; C:focal adhesion; HDA:UniProtKB.
DR   GO; GO:0001772; C:immunological synapse; IDA:UniProtKB.
DR   GO; GO:0016021; C:integral component of membrane; IDA:UniProtKB.
DR   GO; GO:0005887; C:integral component of plasma membrane; IDA:UniProtKB.
DR   GO; GO:0016020; C:membrane; HDA:UniProtKB.
DR   GO; GO:0005886; C:plasma membrane; IDA:UniProtKB.
DR   GO; GO:0097197; C:tetraspanin-enriched microdomain; IDA:UniProtKB.
DR   GO; GO:0031982; C:vesicle; IDA:UniProtKB.
DR   GO; GO:0015485; F:cholesterol binding; IDA:UniProtKB.
DR   GO; GO:0005178; F:integrin binding; IDA:UniProtKB.
DR   GO; GO:0042289; F:MHC class II protein binding; IDA:UniProtKB.
DR   GO; GO:0023026; F:MHC class II protein complex binding; HDA:UniProtKB.
DR   GO; GO:1990459; F:transferrin receptor binding; IPI:BHF-UCL.
DR   GO; GO:0001618; F:virus receptor activity; IMP:UniProtKB.
DR   GO; GO:0000187; P:activation of MAPK activity; IDA:UniProtKB.
DR   GO; GO:0035783; P:CD4-positive, alpha-beta T cell costimulation; IDA:UniProtKB.
DR   GO; GO:0071404; P:cellular response to low-density lipoprotein particle stimulus; ISS:UniProtKB.
DR   GO; GO:0002455; P:humoral immune response mediated by circulating immunoglobulin; IMP:UniProtKB.
DR   GO; GO:0001771; P:immunological synapse formation; IMP:UniProtKB.
DR   GO; GO:0034238; P:macrophage fusion; IDA:UniProtKB.
DR   GO; GO:0014905; P:myoblast fusion involved in skeletal muscle regeneration; ISS:UniProtKB.
DR   GO; GO:0072675; P:osteoclast fusion; ISS:UniProtKB.
DR   GO; GO:0043128; P:positive regulation of 1-phosphatidylinositol 4-kinase activity; IDA:UniProtKB.
DR   GO; GO:1905676; P:positive regulation of adaptive immune memory response; IMP:UniProtKB.
DR   GO; GO:0030890; P:positive regulation of B cell proliferation; IDA:AgBase.
DR   GO; GO:0050861; P:positive regulation of B cell receptor signaling pathway; IMP:UniProtKB.
DR   GO; GO:2000563; P:positive regulation of CD4-positive, alpha-beta T cell proliferation; IDA:UniProtKB.
DR   GO; GO:0008284; P:positive regulation of cell population proliferation; IDA:UniProtKB.
DR   GO; GO:0002863; P:positive regulation of inflammatory response to antigenic stimulus; ISS:UniProtKB.
DR   GO; GO:0050731; P:positive regulation of peptidyl-tyrosine phosphorylation; IDA:UniProtKB.
DR   GO; GO:1904352; P:positive regulation of protein catabolic process in the vacuole; IMP:BHF-UCL.
DR   GO; GO:0070863; P:positive regulation of protein exit from endoplasmic reticulum; IMP:UniProtKB.
DR   GO; GO:1903911; P:positive regulation of receptor clustering; IDA:UniProtKB.
DR   GO; GO:2001190; P:positive regulation of T cell activation via T cell receptor contact with antigen bound to MHC molecule on antigen presenting cell; IDA:UniProtKB.
DR   GO; GO:0050862; P:positive regulation of T cell receptor signaling pathway; IMP:UniProtKB.
DR   GO; GO:2000553; P:positive regulation of T-helper 2 cell cytokine production; IDA:UniProtKB.
DR   GO; GO:0045944; P:positive regulation of transcription by RNA polymerase II; IGI:BHF-UCL.
DR   GO; GO:0008104; P:protein localization; IDA:UniProtKB.
DR   GO; GO:0061462; P:protein localization to lysosome; IMP:BHF-UCL.
DR   GO; GO:0072659; P:protein localization to plasma membrane; IDA:UniProtKB.
DR   GO; GO:0031623; P:receptor internalization; ISS:UniProtKB.
DR   GO; GO:0046813; P:receptor-mediated virion attachment to host cell; TAS:UniProtKB.
DR   GO; GO:1905521; P:regulation of macrophage migration; ISS:UniProtKB.
DR   GO; GO:0031647; P:regulation of protein stability; IMP:BHF-UCL.
DR   GO; GO:0046718; P:viral entry into host cell; TAS:UniProtKB.
DR   Gene3D; 1.10.1450.10; -; 1.
DR   InterPro; IPR018499; Tetraspanin/Peripherin.
DR   InterPro; IPR000301; Tetraspanin_animals.
DR   InterPro; IPR018503; Tetraspanin_CS.
DR   InterPro; IPR008952; Tetraspanin_EC2_sf.
DR   Pfam; PF00335; Tetraspanin; 1.
DR   PIRSF; PIRSF002419; Tetraspanin; 1.
DR   SUPFAM; SSF48652; SSF48652; 1.
DR   PROSITE; PS00421; TM4_1; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Adaptive immunity; Cell membrane; Disulfide bond;
KW   Host cell receptor for virus entry; Host-virus interaction; Immunity;
KW   Lipid-binding; Membrane; Receptor; Reference proteome; Transmembrane;
KW   Transmembrane helix.
FT   CHAIN           1..236
FT                   /note="CD81 antigen"
FT                   /id="PRO_0000219221"
FT   TOPO_DOM        1..12
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000269|PubMed:27881302,
FT                   ECO:0000305|PubMed:1860863"
FT   TRANSMEM        13..33
FT                   /note="Helical"
FT                   /evidence="ECO:0000269|PubMed:27881302"
FT   TOPO_DOM        34..63
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000269|PubMed:27881302"
FT   TRANSMEM        64..84
FT                   /note="Helical"
FT                   /evidence="ECO:0000269|PubMed:27881302"
FT   TOPO_DOM        85..89
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000269|PubMed:27881302"
FT   TRANSMEM        90..112
FT                   /note="Helical"
FT                   /evidence="ECO:0000269|PubMed:27881302"
FT   TOPO_DOM        113..201
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000269|PubMed:27881302"
FT   TRANSMEM        202..224
FT                   /note="Helical"
FT                   /evidence="ECO:0000269|PubMed:27881302"
FT   TOPO_DOM        225..236
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000269|PubMed:27881302,
FT                   ECO:0000305|PubMed:1860863"
FT   BINDING         219
FT                   /note="Cholesterol"
FT                   /evidence="ECO:0000269|PubMed:27881302,
FT                   ECO:0007744|PDB:5TCX"
FT   SITE            116
FT                   /note="Important for interaction with integrin"
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   SITE            144
FT                   /note="Important for interaction with integrin"
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   SITE            148
FT                   /note="Important for interaction with integrin"
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   DISULFID        156..190
FT                   /evidence="ECO:0000269|PubMed:11226150,
FT                   ECO:0000269|PubMed:12437138, ECO:0000269|PubMed:26116703,
FT                   ECO:0000269|PubMed:27881302, ECO:0000269|PubMed:27916518,
FT                   ECO:0007744|PDB:1G8Q, ECO:0007744|PDB:1IV5,
FT                   ECO:0007744|PDB:3X0E, ECO:0007744|PDB:5DFV,
FT                   ECO:0007744|PDB:5DFW, ECO:0007744|PDB:5M2C,
FT                   ECO:0007744|PDB:5M33, ECO:0007744|PDB:5M3D,
FT                   ECO:0007744|PDB:5M3T, ECO:0007744|PDB:5M4R,
FT                   ECO:0007744|PDB:5TCX, ECO:0007744|PDB:6EJG,
FT                   ECO:0007744|PDB:6EJM, ECO:0007744|PDB:6EK2"
FT   DISULFID        157..175
FT                   /evidence="ECO:0000269|PubMed:11226150,
FT                   ECO:0000269|PubMed:12437138, ECO:0000269|PubMed:26116703,
FT                   ECO:0000269|PubMed:27881302, ECO:0000269|PubMed:27916518,
FT                   ECO:0007744|PDB:1G8Q, ECO:0007744|PDB:1IV5,
FT                   ECO:0007744|PDB:3X0E, ECO:0007744|PDB:5DFV,
FT                   ECO:0007744|PDB:5DFW, ECO:0007744|PDB:5M2C,
FT                   ECO:0007744|PDB:5M33, ECO:0007744|PDB:5M3D,
FT                   ECO:0007744|PDB:5M3T, ECO:0007744|PDB:5M4R,
FT                   ECO:0007744|PDB:5TCX, ECO:0007744|PDB:6EJG,
FT                   ECO:0007744|PDB:6EJM, ECO:0007744|PDB:6EK2"
FT   MUTAGEN         116
FT                   /note="K->E: Reduces binding to integrin."
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   MUTAGEN         119
FT                   /note="I->A: No effect on integrin binding."
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   MUTAGEN         121
FT                   /note="K->E: No effect on integrin binding."
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   MUTAGEN         124
FT                   /note="K->E: No effect on integrin binding."
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   MUTAGEN         126
FT                   /note="F->A: No effect on integrin binding."
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   MUTAGEN         144
FT                   /note="K->E: Reduces binding to integrin; when associated
FT                   with E-148."
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   MUTAGEN         148
FT                   /note="K->E: Reduces binding to integrin; when associated
FT                   with E-144."
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   MUTAGEN         186
FT                   /note="F->A: No effect on integrin binding."
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   MUTAGEN         187
FT                   /note="K->E: No effect on integrin binding."
FT                   /evidence="ECO:0000269|PubMed:27993971"
FT   MUTAGEN         188
FT                   /note="E->K,Q: Strongly reduced affinity for HCV protein
FT                   E2; when associated with E-196."
FT                   /evidence="ECO:0000269|PubMed:26116703"
FT   MUTAGEN         188
FT                   /note="E->K: Mildly reduced affinity for HCV protein E2."
FT                   /evidence="ECO:0000269|PubMed:26116703"
FT   MUTAGEN         196
FT                   /note="D->E: Strongly reduced affinity for HCV protein E2;
FT                   when associated with K-188 or Q-188."
FT                   /evidence="ECO:0000269|PubMed:26116703"
FT   MUTAGEN         196
FT                   /note="D->K,Q,R: Strongly reduced affinity for HCV protein
FT                   E2."
FT                   /evidence="ECO:0000269|PubMed:26116703"
FT   MUTAGEN         219
FT                   /note="E->A,Q: Reduced affinity for cholesterol binding."
FT                   /evidence="ECO:0000269|PubMed:27881302"
FT   HELIX           10..36
FT                   /evidence="ECO:0007829|PDB:5TCX"
FT   HELIX           57..80
FT                   /evidence="ECO:0007829|PDB:5TCX"
FT   HELIX           81..84
FT                   /evidence="ECO:0007829|PDB:5TCX"
FT   HELIX           113..115
FT                   /evidence="ECO:0007829|PDB:6U9S"
FT   HELIX           116..136
FT                   /evidence="ECO:0007829|PDB:5M33"
FT   HELIX           141..154
FT                   /evidence="ECO:0007829|PDB:5M33"
FT   STRAND          158..160
FT                   /evidence="ECO:0007829|PDB:5M3D"
FT   HELIX           163..165
FT                   /evidence="ECO:0007829|PDB:5M33"
FT   HELIX           166..171
FT                   /evidence="ECO:0007829|PDB:5M33"
FT   HELIX           172..174
FT                   /evidence="ECO:0007829|PDB:5M2C"
FT   HELIX           181..185
FT                   /evidence="ECO:0007829|PDB:5M33"
FT   HELIX           190..199
FT                   /evidence="ECO:0007829|PDB:5M33"
FT   HELIX           202..230
FT                   /evidence="ECO:0007829|PDB:5TCX"
SQ   SEQUENCE   236 AA;  25809 MW;  EB9BD7671AC91B4A CRC64;
     MGVEGCTKCI KYLLFVFNFV FWLAGGVILG VALWLRHDPQ TTNLLYLELG DKPAPNTFYV
     GIYILIAVGA VMMFVGFLGC YGAIQESQCL LGTFFTCLVI LFACEVAAGI WGFVNKDQIA
     KDVKQFYDQA LQQAVVDDDA NNAKAVVKTF HETLDCCGSS TLTALTTSVL KNNLCPSGSN
     IISNLFKEDC HQKIDDLFSG KLYLIGIAAI VVAVIMIFEM ILSMVLCCGI RNSSVY
//
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