RIAM activates integrins by linking talin to ras GTPase membrane-targeting sequences.

ABSTRACT: Rap1 small GTPases interact with Rap1-GTP-interacting adaptor molecule (RIAM), a member of the MRL (Mig-10/RIAM/Lamellipodin) protein family, to promote talin-dependent integrin activation. Here, we show that MRL proteins function as scaffolds that connect the membrane targeting sequences in Ras GTPases to talin, thereby recruiting talin to the plasma membrane and activating integrins. The MRL proteins bound directly to talin via short, N-terminal sequences predicted to form amphipathic helices. RIAM-induced integrin activation required both its capacity to bind to Rap1 and to talin. Moreover, we constructed a minimized 50-residue Rap-RIAM module containing the talin binding site of RIAM joined to the membrane-targeting sequence of Rap1A. This minimized Rap-RIAM module was sufficient to ta

SUBMITTER: Lee HS 

PROVIDER: S-EPMC2643525 | biostudies-literature | 2009 Feb

REPOSITORIES: biostudies-literature