Domain

Ras-like guanine nucleotide exchange factor, N-terminal (IPR000651)

Short name: Ras-like_Gua-exchang_fac_N

Domain relationships

None.

Description

The N-terminal domain of guanine nucleotide exchange factor (GEF) for Ras-like GTPases is also called REM domain (Ras exchanger motif). REM contacts the GTPase and is assumed to participate in the catalytic activity of the exchange factor. Proteins with the REM domain include Sos1 and Sos2, which relay signals from tyrosine-kinase mediated signalling to Ras, RasGRP1-4, RasGRF1,2, CNrasGEF, and RAP-specific nucleotide exchange factors, to name a few [PMID: 18541156, PMID: 18236214, PMID: 7786285, PMID: 8259209, PMID: 8479541, PMID: 16452984, PMID: 12628188, PMID: 9690470].

The crystal structure of the GEF region of human Sos1 complexes with Ras has been solved [PMID: 9690470]. The structure consists of two distinct alpha helical structural domains: the N-terminal domain which seems to have a purely structural role and the C-terminal domain which is sufficient for catalytic activity and contains all residues that interact with Ras. A main feature of the catalytic domain is the protrusion of a helical hairpin important for the nucleotide-exchange mechanism. The N-terminal domain is likely to be important for the stability and correct placement of the hairpin structure.

This entry represents a domain found in several GEF for Ras-like small GTPases which lies N-terminal to the RasGef (Cdc25-like) domain.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
CDD
Pfam
PROSITE profiles
SMART