['TGFbeta (transforming growth factor beta) is a multifunctional cytokine and a potent regulator of cell growth, migration and differentiation in many cell types. In the vascular system, TGFbeta plays crucial roles in vascular remodelling, but the signalling pathways involved remain poorly characterized.', 'Using the model of porcine aortic endothelial cells, we demonstrated that TGFbeta stimulates cellular spreading when cells are on collagen I. TGFbeta-stimulated Rac1-GTP accumulation, which was associated with increased MAPK (mitogen-activated protein kinase) p38 phosphorylation. Furthermore, ectopic expression of a dominant-negative Rac mutant, or treatment of the cells with the p38 pharmacological inhibitor SB203580, abrogated TGFbeta-induced cell spreading. Our results demonstrate for the first time that prolonged exposure to TGFbeta stimulates endothelial cell hypertrophy and flattening. Collectively, these data indicate that TGFbeta-induced cell spreading and increase in cell surface areas occurs via a Rac-p38-dependent pathway.'] Does tGFbeta1 regulate endothelial cell spreading and hypertrophy through a Rac-p38-mediated pathway?