S100 (S100)

entry list
S100 (S100) family consists of at least thirteen distinct isoforms. S100's A1 _ A10 in humans are all encoded on chromosome 1; whether they are subject to coordinate expression has not been determined. Most have been demonstrated to be dimers. S100a (S100A1)2 regulates giant protein kinase. The NMR solution structure of (S100B)2 free and complexed with the C-terminal peptide (367-388) from protein p53 shows the peptide interacting primarily with _-helices E1 and E2 of one monomer and _-helix F2 of the other monomer [33]. S100A9 (p11) forms a heterotetramer with annexin II; the crystal structure of (S100A9)2 complexed peptide 1-13 from annexin II shows a similar orientation of the peptide with the N-acyl group against _-helix E1 [34]. Certain neurons are characterized by their contents of S100, as well as contents of parvalbumins. Several S100's function in culture as neurite extension factors [35]; whether S100 functions extracellularly under non-pathological conditions has yet to be established.