an adaptor protein that is an epidermal growth factor receptor (EGFR) substrate. Enhances EGF-dependent mitogenic signals. Member of a family of actin barbing and capping proteins. Promotes filopodial protrusions. Complexes containing Eps8/Abi1/PI3K/Sos-1 mediate Rac activation following EGFR signaling. Involved in endocytosis of EGFR by binding to the Rab5-specific GTPase activating protein USP6N. Binds to IRSp53, which binds small the small GTPases Rac and Cdc42, and which regulates actin dynamics. Involved in the actin-remodeling activity in cultured cerebellar neurons. Regulates the actin-remodeling activities of NMDA and ethanol in neurons. Eps8 knockout mice show behavioral resistance to ethanol. Expressed in all tissues analyzed, including heart, brain, placenta, lung, liver, skeletal muscle, kidney and pancreas. Expressed in all epithelial and fibroblastic lines examined and in some, but not all, hematopoietic cells. Note: This description may include information from UniProtKB.