Ras effector protein that functions as a guanine nucleotide exchange (GEF) for RAB5B and RAB31, by exchanging bound GDP for free GTP. Required for normal RAB31 function. Interacts with CD2AP, RAB5B, RAB31 and BIN1. Activation of tyrosine phosphorylation signaling induces translocation to cytoplasmic vesicles. Widely expressed. Belongs to the RIN (Ras interaction/interference) family. Aberrant splicing. Truncated N-terminus. Intron retention.