Group Activities

Science's STKE  06 May 2003:
Vol. 2003, Issue 181, pp. tw181-TW181
DOI: 10.1126/stke.2003.181.tw181

Integrins comprise a globular ligand-binding head and two flexible rod-like stalks that contain the transmembrane and cytoplasmic regions of the integrin α and β chains. Although the details of the integrin activation mechanism are controversial, several proposals agree that the stalks splay apart on activation and that integrin activation is accompanied by clustering of the receptors. Li et al. (see the Perspective by Hynes) found two mutations in the transmembrane helix of the β subunit that enhanced the tendency of the β subunit to form homotrimers and that also induced clustering and constitutive phosphorylation of focal adhesion kinase. Homo-oligomerization may drive activation by stabilizing the activated state while simultaneously inducing the formation of clusters.

R. Li, N. Mitra, H. Gratkowski, G. Vilaire, R. Litvinov, C. Nagasami, J. W. Weisel, J. D. Lear, W. F. DeGrado, J. S. Bennett, Activation of integrin αIIbβ3 by modulation of transmembrane helix associations. Science 300, 795-798 (2003). [Abstract] [Full Text]

R. O. Hynes, Changing partners. Science 300, 755-756 (2003). [Summary] [Full Text]