FunctionMay act as a link between RND2 signaling and regulation of the actin cytoskeleton (By similarity). Required to coordinate membrane tubulation with reorganization of the actin cytoskeleton during endocytosis. Binds to lipids such as phosphatidylinositol 4,5-bisphosphate and phosphatidylserine and promotes membrane invagination and the formation of tubules. Also enhances actin polymerization via the recruitment of WASL/N-WASP, which in turn activates the Arp2/3 complex. Actin polymerization may promote the fission of membrane tubules to form endocytic vesicles. May be required for the lysosomal retention of FASLG/FASL.
Tissue specificityVery highly expressed in the epithelial cells of the gastrointestinal tract, respiratory, reproductive and urinary systems. Also highly expressed in brown adipose tissue, cardiomyocytes, enteric ganglia and glucagon producing cells of the pancreas. Expressed in germ cells of the testis and all regions of the brain.
Involvement in diseaseNote=A chromosomal aberration involving FNBP1 is found in acute leukemias. Translocation t(9;11)(q34;q23) with MLL. The relatively low incidence of the MLL-FNBP1 fusion protein in acute leukemia may reflect the marginal capacity of this fusion protein to induce cellular transformation.
Sequence similaritiesBelongs to the FNBP1 family. Contains 1 FCH domain. Contains 1 REM (Hr1) repeat. Contains 1 SH3 domain.
Cellular localizationCytoplasm. Cytoplasm > cytoskeleton. Cytoplasm > cell cortex. Lysosome. Cytoplasmic vesicle. Cell membrane. Enriched in cortical regions coincident with F-actin. Also localizes to endocytic vesicles and lysosomes.