An area of cytokine research that has received relatively little attention is the cytokine-induced cellular responses that are not directly related to mitosis. An example of a cytokine capable of inducing these types of cellular activities is TGF-beta. Earlier, we have shown that TGF-beta induces cellular hypertrophy in cultured, vascular, smooth muscle cells and, concomitantly, the stimulated cells exhibited an enhanced level of f -actin. This observation led to a series of studies on the cellular adhesion molecule, fibronectin, and its interactions with its receptor. With our collaborators, we have shown that the minimum essential amino acid sequence for the CS1 activity has been shown to be Leu-Asp-Val. In addition, we found that a weak adhesive activity shown by CS1-E and CS1-C peptides is due to GPEIL C-terminal sequence. The amino terminal domain of CS1 enhances the CSI-A activity by stabilizing the conformation of the C-terminal GPEILDVPST sequence. A study is underway to verify this prediction by NMR method.
