Drebrin is a major neuronal F-actin binding protein involved in the control of actin dynamics and neuronal morphogenesis. Three major isoforms of drebrin, resulting from alternative splicing of a single gene, have been identified in the brain: the embryonic isoforms designated E1 and E2 and the adult or A isoform (95-120 kDa). An additional truncated form of drebrin A, s-drebrin/A2 (42 kDa), is specifically expressed in the adult brain, but not in non-neuronal tissues. Drebrin is also widely