ABI1

This gene encodes a member of the Abelson-interactor family of adaptor proteins. These proteins facilitate signal transduction as components of several multiprotein complexes, and regulate actin polymerization and cytoskeletal remodeling through interactions with Abelson tyrosine kinases. The encoded protein plays a role in macropinocytosis as a component of the WAVE2 complex, and also forms a complex with EPS8 and SOS1 that mediates signal transduction from Ras to Rac. This gene may play a role in the progression of several malignancies including melanoma, colon cancer and breast cancer, and a t(10;11) chromosomal translocation involving this gene and the MLL gene has been associated with acute myeloid leukemia. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene, and a pseudogene of this gene is located on the long arm of chromosome 14.

Full Name

abl interactor 1

Function

May act in negative regulation of cell growth and transformation by interacting with nonreceptor tyrosine kinases ABL1 and/or ABL2. May play a role in regulation of EGF-induced Erk pathway activation. Involved in cytoskeletal reorganization and EGFR signaling. Together with EPS8 participates in transduction of signals from Ras to Rac. In vitro, a trimeric complex of ABI1, EPS8 and SOS1 exhibits Rac specific guanine nucleotide exchange factor (GEF) activity and ABI1 seems to act as an adapter in the complex. Regulates ABL1/c-Abl-mediated phosphorylation of ENAH. Recruits WASF1 to lamellipodia and there seems to regulate WASF1 protein level. In brain, seems to regulate the dendritic outgrowth and branching as well as to determine the shape and number of synaptic contacts of developing neurons.

Biological Process

Actin polymerization or depolymerization
Fc-gamma receptor signaling pathway involved in phagocytosis
Negative regulation of cell population proliferation
Peptidyl-tyrosine phosphorylation
Transmembrane receptor protein tyrosine kinase signaling pathway
Vascular endothelial growth factor receptor signaling pathway
Viral process

Cellular Location

Cytoskeleton; Nucleus; Cytoplasm; Lamellipodium; Filopodium; Growth cone; Postsynaptic density. Localized to protruding lamellipodia and filopodia tips. Also localized to neuronal growth cones and synaptosomes. May shuttle from the postsynaptic densities to the nucleus (By similarity).

Involvement in disease

A chromosomal aberration involving ABI1 is a cause of acute leukemias. Translocation t(10;11)(p11.2;q23) with KMT2A/MLL1. ABI1 isoform 2 was found to be present in acute leukemia KMT2A/MLL1-ABI1 fusion transcript.

PTM

Phosphorylated on tyrosine residues after serum stimulation or induction by v-Abl. Seems to be phosphorylated at Tyr-53 by ABL1, required for nuclear but not for synaptic localization.