Cell membrane-cytoskeleton-associated protein that plays a role in the regulation of actin polymerization at the barbed end of actin filaments. Prevents F-actin heterodimeric capping protein (CP) activity at the leading edges of migrating cells, and hence generates uncapped barbed ends and enhances actin polymerization (PubMed:26466680). Plays a role in cell protrusion formations; involved in cell polarity, lamellipodial assembly, membrane ruffling and macropinosome formations (PubMed:19846667, PubMed:26466680, PubMed:26578515). Involved as well in cell migration and invadopodia formation during wound healing (PubMed:19846667, PubMed:26466680, PubMed:26578515). Required for CD28-mediated stimulation of NF-kappa-B signaling, involved in naive T cells activation, maturation into T memory cells, and differentiation into T helper and T regulatory cells (PubMed:27647348, PubMed:27647349, PubMed:28112205).