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, however, seems unable to nucleate filaments (PubMed:16054028). Plays a role in lamellipodial protrusion formations and cell migration (PubMed:16054028). Homodimer (By similarity). Interacts (via C-terminus) with heterodimeric capping protein (CP); this interaction uncaps barbed ends capped by CP, enhances barbed-end actin polymerization and promotes lamellipodial formation and cell migration (PubMed:16054028). Interacts with MYO1E (By similarity). Interacts with TRIO (By similarity). Found on macropinosomes (By similarity). Colocalized with heterodimeric capping protein (CP) and F-actin in lamellipodia but not with F-actin in stress fibers (PubMed:16054028). The C-terminus is necessary for localization to the cell membrane. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Belongs to the CARMIL family. Truncated N-terminus. Truncated N-terminus.