S100 calcium-binding protein B

S100 calcium-binding protein B (S100-B) exists as a homodimer of either two A or B chains or as a heterodimer. It is predominantly found in the brain. S100-B acts as a neurotrophic factor and neuronal survival protein. In adults, it is elevated with nervous system damage, making it a potential clinical marker. Altered expression of this gene has been implicated in several neurological diseases. S100-B weakly binds calcium but binds zinc very tightly in distinct binding sites with different affinities for both ions on each monomer. Physiological concentrations of potassium ion antagonize the binding of both divalent cations, especially affecting high-affinity calcium-binding sites. Binds to and initiates the activation of STK38 by releasing autoinhibitory intramolecular interactions within the kinase. Interaction with AGER after myocardial infarction may play a role in myocyte apoptosis by activating ERK1/2 and p53/TP53 signaling. Could assist ATAD3A cytoplasmic processing, preventing aggregation, and favoring mitochondrial localization.

Swiss-Prot Accession Number: P04271