protein S100-B; S100 Ca+2-binding protein B; S-100 protein subunit beta; S-100 protein beta chain (S100B)

Function

• weakly binds Ca+2
• binds Zn+2 very tightly
• distinct binding sites with different affinities exist for both Ca+2 & Zn+2 on each monomer
• physiological concentrations of K+ antagonize the binding of both Ca+2 & Zn+2, especially affecting high-affinity Ca+2-binding sites
• binds to & initiates activation of STK38 by releasing autoinhibitory intramolecular interactions within STK38
• the S100B dimer binds two molecules of STK38 (putative)
• the S100B dimer interacts with two molecules of CAPZA1
• in addition to metal-ion binding, role in regulation of protein phosphorylation in brain

Structure

• dimer of either two alpha chains, or two beta chains, or one alpha & one beta chain.
• belongs to the S-101 family
• contains 2 EF-hand domains

Compartment

cytoplasm, nucleus

Expression

• predominant among the water-soluble brain proteins
• found in a variety of other tissues

Laboratory

• S100-beta in CSF
• S100-beta in serum/plasma

More general terms

• protein subunit
• Ca+2 binding protein

Additional terms

• S100-beta in serum/plasma

Component of

• S100 Ca+2-binding protein

Database

• UniProt: http://www.uniprot.org/uniprot/P04271.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=6285
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:6285
• OMIM: https://mirror.omim.org/entry/176990