Transient induction of vinculin gene expression in 3T3 fibroblasts stimulated by serum-growth factors.

Abstract

When stimulated with serum, quiescent Balb/C-3T3 fibroblasts were found to induce vinculin transcription transiently within 30 min, followed by accumulation of vinculin mRNA and protein synthesis between 2 and 4 h after stimulation and a decrease to the basal level by 6-8 h. Platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), and 12-O-tetradecanoylphorbol-13-acetate (TPA) each could elicit a similar response, albeit to a lesser extent, whereas epidermal growth factor (EGF) was inefficient in inducing vinculin expression. In cells stimulated with serum and cycloheximide, vinculin expression was superinduced and vinculin mRNA levels persisted longer than in cells stimulated with serum alone. Cells arrested in the presence of serum by anchorage denial in methyl cellulose suspension culture also induced vinculin expression and formed large vinculin positive plaques when reattaching and spreading on the substrate in the presence of serum. Cells replated from suspension culture in the absence of serum on either plastic or extracellular matrix (ECM) components were capable of extensive spreading, but failed to elevate vinculin expression and displayed diffuse vinculin staining. The results indicate that the changes in vinculin organization and expression in response to growth factor stimulation may reflect either a necessary step in the progression through the cell cycle or a response related to complex cellular processes such as wound repair and embryogenesis.