Low level expression of calcium-sensor protein VILIP induces cAMP-dependent differentiation in rat C6 glioma cells

Wild-type visinin-like-protein (VILIP) and a myristoylation-deficient VILIP mutant, when stably expressed at low levels in C6 cells, enhances or reduces the basal cAMP-level, respectively. The morphology of wild-type VILIP-transfected cells resembles that of differentiated astrocytes, whereas the myristoylation mutant shows a phenotype similar to parental cells, but with reduced cell growth. In both parental and myristoylation mutant cells a differentiated phenotype similar to that produced by wild-type VILIP-transfected cells is inducible with 8-bromo-cAMP. The changed morphology parallels an increase in the expression of the astrocytic differentiation marker glial fibrillary acidic protein (GFAP) in wild-type VILIP-transfected and cAMP-differentiated cells, but a decrease of GFAP in myristoylation mutant cells. These results suggest that depending on myristoylation, low level ectopic expression of VILIP affects basal cAMP homeostasis differentially, thereby influencing differentiation of C6 model cells.