DISULFIDE-LINKED S100-BETA DIMERS AND SIGNAL TRANSDUCTION

S100beta is a calcium-binding protein with neurotrophic and mitogenic activities, both of which may be mediated by the protein's ability to stimulate an increase in intracellular free calcium ([Ca2+]i). These extracellular trophic activities of S100beta require a disulfide-linked, dimeric form of the protein. In this chapter, we present a minireview on the current state of knowledge concerning extracellular functions of S100beta, with emphasis on the potential relevance of these activities to neuropathological disorders. We also report a simplified procedure for preparation of pharmacological amounts of biologically active S100beta dimers, based on the finding that formation of disulfide-linked S100beta dimers can be stimulated by the presence of calcium or lipid.