CALCIUM-DEPENDENT AND MYRISTOYL-DEPENDENT SUBCELLULAR-LOCALIZATION OFTHE NEURONAL CALCIUM-BINDING PROTEIN VILIP IN TRANSFECTED PC12 CELLS

Wild-type neuronal calcium-binding protein VILIP (visinin-like protein ), and a myristoylation mutant of VILIP which lacks the consensus sequ ence for N-terminal myristoylation, have been stably transfected in PC 12 cells. Immunocytochemical studies of VILIP-transfected PC12 cells h ave revealed that wild-type VILIP is strongly concentrated at the cell membrane, particularly at cell-cell contact sites, but is also distri buted throughout the cytosol at moderate levels. In contrast, myristoy lation-mutant VILIP shows a more even distribution, with significantly less association at cell-cell contact sites. Western blot analysis of subcellular fractions has shown that wild-type VILIP associates in a calcium-dependent manner with membrane fractions, whereas the myristoy lation mutant only weakly associates with this fraction. Therefore, a calcium-myristoyl switch seems to be a major, but not sole determinant for the association of VILIP with membranes in Living cells. (C) 1997 Elsevier Science Ireland Ltd.