Functions as a guanine nucleotide exchange factor (GEF) with specificity for RAB11A and RAB25 (, ). Inhibits the auto- and transphosphorylation activity of BTK. Plays a negative regulatory role in BTK-related cytoplasmic signaling in B-cells. May be involved in BCR-induced apoptotic cell death.
Subcellular locations: Cytoplasmic vesicle membrane, Mitochondrion
Colocalizes with RAB11A on cytoplasmic vesicle membranes.
Highly expressed in testis and ovaries. It is also expressed in a variety of tissues including spleen, lymph node, thymus, bone marrow, fetal liver, colon, small intestine and prostate.