Distinct functional roles of the two intracellular phosphatase like domains of the receptor-linked protein tyrosine phosphatases LCA and LAR.

摘要: Protein tyrosine phosphorylation is regulated by both protein kinases and phosphatases (PTPases). Recently, the structures of a family PTPases have been described. In order to study structure-function relationships receptor-linked PTPases, we analyzed effects deletion point mutations within cytoplasmic region LCA LAR. We show that first two domains has enzyme activity itself, one cysteine residue in domain LAR absolutely required for activity. The second PTPase like do not detectable catalytic using variety substrates, but sequences influence substrate specificity. functional significance stretch 10 highly conserved amino acid residues surrounding critical located was assessed. At most positions, any substitution severely reduced activity, while missense at other positions tested could be tolerated varying degrees depending on substitution. It suggested this acids may part center PTPases.