May play a cooperative role in NF2-mediated growth suppression of cells. May act as a modulator of small G protein RAB- and RAP-mediated neuronal signal transduction and vesicular transportation pathways (By similarity). Interacts with GJA1. Interaction with GJA1 induces its degradation. Interacts (via RUN domain) with NF2 (via C-terminus). Interacts with RAB3A, RAB4A, RAB5A, RAB8A, RAB11A, RAP1A, RAP1B, RAP2A, RAP2B and PDCD6I. No interaction with RAB27A. No interaction with GJB1 or GJD2. Expressed in brain, liver, kidney and testis. Moderately expressed in heart, very weakly in lung and muscle. Not expressed in spleen. Belongs to the small G protein signaling modulator family.