Members of this family, which are predominantly found in eukaryotic signal recognition particle receptor alpha, consist of a central six-stranded anti-parallel beta-sheet sandwiched by helix alpha1 on one side and helices alpha2-alpha4 on the other. They interact with the small GTPase SR-beta, forming a complex that matches a class of small G protein-effector complexes, including Rap-Raf, Ras-PI3K(gamma), Ras-RalGDS, and Arl2-PDE(delta) [1]. Structurally the alpha subunit is SNARE-like.

1: Structural basis for the function of the beta subunit of the eukaryotic signal recognition particle receptor. Schwartz T, Blobel G; Cell. 2003;112:793-803. PMID:12654246