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- *******************************************************
- * 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. 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 five C's are probably 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: December 1992 / Text revised.
-
- [ 1] Hynes R.O.
- Cell 48:549-554(1987).
- [ 2] Albelda S.M., Buck C.A.
- FASEB J. 4:2868-2880(1990).
- [ 3] Sheppard D., Rozzo C., Starr L., Quaranta V., Erle D.J., Pytela R.
- J. Biol. Chem. 265:11502-11507(1990).
- [ 4] Erle D.J., Rueegg C., Sheppard D., Pytela R.
- J. Biol. Chem. 266:11009-11016(1991).
- [ 5] Moyle M., Napier M.A., McLean J.W.
- J. Biol. Chem. 266:19650-19658(1991).
-