The neuronal EF-hand calcium-binding protein visinin-like protein-3 is expressed in cerebellar Purkinje cells and shows a calcium-dependent membrane association

Visinin-like protein-3 is a member of the family of intracellular neuronal calcium sensors belonging to the superfamily of EF-hand proteins. Members o f this family are involved in the calcium-dependent regulation of signal tr ansduction cascades. To gain insights into the characteristics of visinin-l ike protein-3, we have generated specific antibodies against visinin-like p rotein-3 and determined the developmental and tissue distribution of the pr otein and its exact cellular and subcellular localization. Expression of vi sinin-like protein-3 protein appeared late in development mainly in the cer ebellum. It is strongly expressed in cerebellar Purkinje cells. The protein expression results were further confirmed by in situ hybridization and com pared with hippocalcin messenger RNA localization. Native cerebellar visini n-like protein-3 was shown to bind calcium and to associate in a calcium-de pendent manner with membrane fractions during subcellular fractionation. Re combinant wild-type visinin-like protein-3 was shown to be N-terminally myr istoylated in transfected cells. The membrane association was strongly redu ced for the non-myristoylated mutant of visinin-like protein-3 in transfect ed cells. These results suggest that visinin-like protein-3, which is mainly expresse d in Purkinje cells in vivo, shows a calcium-dependent association with cel l membranes which is mediated by a calcium-myristoyl switch. (C) 2000 IBRO. Published by Elsevier Science Ltd.