S100 (S100)
entry list
alignment
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.