S100beta (human) (rec.)

S100 protein family consists of highly homologous Ca2+ binding proteins that possess two EF-hand motifs. Most S100 proteins exist as dimers (frequently homodimers) within cells. Exclusively expressed in vertebrates, S100 is implicated in various intracellular and extracellular regulatory activities. Studies indicate that S100 proteins are involved in the inhibition of protein phosphorylation, inhibition of cytoskeletal constituent assembly, regulation of Ca2+ homeostasis, stimulation of enzyme activities, and interaction with transcription factors. S100B is abundant in the nervous system where it is predominantly expressed in astrocytes, oligodendrocytes and Schwann cells. When secreted by astrocytes, S100B has neurotrophic effects during development and nerve regeneration at physiologic (nanomolar) concentrations. High (micromolar) concentration of S100B, however, has shown to be neurotoxic, participating in the physiology of neurodegenerative disorders.