The short peptide RGDS (Arg-Gly-Asp-Ser) is a synthetic cell adhesion factor. RGDS is known to mediate cell adhesion to several extracellular matrix components and cell-cell interactions. RGDS peptide has been shown to directly interact with caspase 8 and 9 and activate it, which indicates an unexpected pro-apoptotic effect due to intracellular effects.
Ortega-Velazquez, R. et al. FASEB. 17, 1529 (2003).