FNBP1

The protein encoded by this gene is a member of the formin-binding-protein family. The protein contains an N-terminal Fer/Cdc42-interacting protein 4 (CIP4) homology (FCH) domain followed by a coiled-coil domain, a proline-rich motif, a second coiled-coil domain, a Rho family protein-binding domain (RBD), and a C-terminal SH3 domain. This protein binds sorting nexin 2 (SNX2), tankyrase (TNKS), and dynamin; an interaction between this protein and formin has not been demonstrated yet in human.

Formin Binding Protein 1

May 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 the late stage of clathrin-mediated 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.

Endocytosis Source: UniProtKB-KW
Signal transduction Source: InterPro

Cytoskeleton; Lysosome; Cytoplasm; Cell membrane; Cell cortex; Cytoplasmic vesicle; Clathrin-coated pit. Enriched in cortical regions coincident with F-actin. Also localizes to endocytic vesicles and lysosomes.

A chromosomal aberration involving FNBP1 is found in acute leukemias. Translocation t(9;11)(q34;q23) with KMT2A/MLL1. The relatively low incidence of the KMT2A/MLL1-FNBP1 fusion protein in acute leukemia may reflect the marginal capacity of this fusion protein to induce cellular transformation.