{PDOC00216}
{PS00243; INTEGRIN_BETA}
{BEGIN}
*******************************************************
* Integrins beta chain cysteine-rich domain signature *
*******************************************************
Integrins [1,2] are a large family of cell surface receptors that mediate cell
to cell as well as cell to matrix adhesion. Some integrins recognize the R-G-D
sequence in their extracellular matrix protein ligand. Structurally, integrins
consist of a dimer of an alpha and a beta chain. Each subunit has a large
N-terminal extracellular domain followed by a transmembrane domain and a short
C-terminal cytoplasmic region. Some receptors share a common beta chain while
having different alpha chains. The sequence of a number of different beta
chains has been determined and are listed below:
- Integrin beta-1, which associates with alpha-1 to form a laminin receptor,
with alpha-2 to form a collagen receptor, with alpha-4 to interact with
VCAM-1, with alpha-5 to form a fibronectin receptor, and with alpha-8.
- Integrin beta-2, which associates with alpha-L (LFA-1) to interact with
ICAM-1, and with alpha-M (MAC-1) or alpha-X (p150,95) to form the receptor
for the iC3b fragment of the third complement component.
- Integrin beta-3, which associates with alpha-IIB to form a receptor for
fibrinogen, fibronectin, vitronectin and VWF, and with alpha-V to form a
vitronectin receptor.
- Integrin beta-4, which associates with alpha-6.
- Integrin beta-5, which associates with alpha-V.
- Integrin beta-6 [3].
- Integrin beta-7 [4].
- Integrin beta-8, which associates with alpha-V [5].
- The Drosophila myospheroid protein, a probable integrin beta chain.
All the integrin beta chains contain four repeats of a forty amino acid region
in the C-terminal extremity of their extracellular domain. Each of the repeats
contains eight cysteines. We have developed a pattern from a section of the
repeated region that includes five of these conserved cysteines.
-Consensus pattern: C-x-[GNQ]-x(1,3)-G-x-C-x-C-x(2)-C-x-C
[The 5 C's may be involved in disulfide bonds]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Note: The pattern will not pick up the first of the four repeats, the spacing
of the cysteine residues being different in that repeat.
-Last update: May 2004 / Text revised.
[ 1] Hynes R.O.
"Integrins: a family of cell surface receptors."
Cell 48:549-554(1987).
PubMed=3028640
[ 2] Albelda S.M., Buck C.A.
"Integrins and other cell adhesion molecules."
FASEB J. 4:2868-2880(1990).
PubMed=2199285
[ 3] Sheppard D., Rozzo C., Starr L., Quaranta V., Erle D.J., Pytela R.
"Complete amino acid sequence of a novel integrin beta subunit (beta
6) identified in epithelial cells using the polymerase chain
reaction."
J. Biol. Chem. 265:11502-11507(1990).
PubMed=2365683
[ 4] Erle D.J., Rueegg C., Sheppard D., Pytela R.
"Complete amino acid sequence of an integrin beta subunit (beta 7)
identified in leukocytes."
J. Biol. Chem. 266:11009-11016(1991).
PubMed=2040616
[ 5] Moyle M., Napier M.A., McLean J.W.
"Cloning and expression of a divergent integrin subunit beta 8."
J. Biol. Chem. 266:19650-19658(1991).
PubMed=1918072
{END}