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protein tyrosine phosphatases

Tuesday 14 February 2006

The protein tyrosine phosphatase (PTP) superfamily of enzymes functions in a coordinated manner with protein tyrosine kinases to control signalling pathways that underlie a broad spectrum of fundamental physiological processes.

PTP1B and TC-PTP

PTP1B and TC-PTP are closely related protein tyrosine phosphatases, sharing 74% homology in their catalytic domain. However, their cellular localization, function, and regulation are found to be different.

Their substrate specificity has implicated these enzymes in various signaling pathways, regulating metabolism, proliferation and cytokine signaling.

For instance, PTP1B has been shown to regulate the activation of cytokine receptors through the dephosphorylation of specific members of the JAK family, namely JAK2 and TYK2, whereas TC-PTP is involved in the modulation of cytokine signaling via JAK1 and JAK3 molecules.

References

- Tonks NK. Protein tyrosine phosphatases: from genes, to function, to disease. Nat Rev Mol Cell Biol. 2006 Nov;7(11):833-46. PMID: 17057753

- Bourdeau A, Dube N, Tremblay ML. Cytoplasmic protein tyrosine phosphatases, regulation and function: the roles of PTP1B and TC-PTP. Curr Opin Cell Biol. 2005 Apr;17(2):203-9. PMID: 15780598