14-3-3 protein: Encyclopedia II - 14-3-3 protein - Properties of 14-3-3 proteins

14-3-3 protein - Properties of 14-3-3 proteins

There are seven genes that encode 14-3-3s in most mammals and 13-15 genes in many higher plants, though typically in fungi they are present only in pairs. Protists, some algae, and other 'lower' forms of life have at least one. Eukaryotes can tolerate the loss of an 14-3-3 isoform if multiple isoforms are present, however deletion of all 14-3-3s (as experimentally determined in yeast) results in death.

14-3-3 proteins can be considered evolved members of the TetratricoPeptide Repeat superfamily, generally have 9 or 10 alpha helices, and usually form homo- and/or hetero-dimer interactions along their amino-termini helices. These proteins contain a number of known common modification domains, including regions for divalent cation interaction, phosphorylation & acetylation, and proteolytic cleavage, among others established and predicted.

There are common recognition motifs for 14-3-3 proteins that contain phosphorylated serines or threonines; Mode 1 is Rxx[pS/pT][SGP] & Mode 2 Rxxx[pS/pT][SGP] (where an 'x' can be several, but not all of the 20 amino acids and a lower case 'p' indicates the site of phosphorylation) but also binding to non-phosphorylated ligands has been reported. This interaction occurs along a so called binding groove or cleft that is amphipathic in nature. To date, the crystal structures of six classes of these proteins has been resolved and deposited in the public domain.

Adapted from the Wikipedia article "Properties of 14-3-3 proteins", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki