In search of DUSP specificity

Dual specificity phosphatases (DUSP) are enzymes that dephosphorylate both phosphoserine/threonine and phosphotyrosine residues on one substrate. Most of them specifically dephosphorylate family mitogen-activated protein kinases (MAPK). Number of DUSPs increases with complexity of organisms and in human genome there are 25 DUSPs described. Some DUSPs can dephosphorylate only one protein while other interact with wider spectrum of substrates. Except for substrate specificity DUSPs differ in expression, subcellular localization etc. Although first DUSPs were described about 20 years ago, a clear factor responsible for their substrate specificity is not known. This works uses in silico methods to discover and describe similarities and differences between DUSPs which may be important in determining DUSP specificity. Key words: phosphatase, kinase, DUSP, MAPK, substrate specificity, conservation of residues, phylogenetic tree, in silico method