Difference between revisions of "Phosphatase Subfamily PTPRK"

Revision as of 00:44, 24 February 2015

Phosphatase Classification: Fold CC1:Superfamily CC1: Family PTP: Subfamily PTPRK

PTPRG is a receptor PTP family involved in metazoan neural development and maybe cancer.

Evolution

PTPRK subfamily is vertebrate specific. There are four copies in human.

Domain Structure

PTPRK has dual intracellular catalytic domains. The canonical extracellular domain combination is a MAM domain, Ig domain and multiple FN3 domain.

MAM domain is essential for homophilic cell-cell interaction and helps determine the specificity of these interactions. Truncated PTPRM is properly expressed at the cell surface but fails to promote cell-cell adhesion. Homophilic cell adhesion is fully restored in a chimeric PTPRM molecule containing the MAM domain of PTPRK. However, this chimeric RPTP mu does not interact with either PTPRK or PTPRM [1].

Functions

PTPRK and PTPRM mediates homophilic cell-cell interaction [1, 2].

PTPRK

PTPRK is a putative tumor suppressor [3]. PTPRK influences transactivating activity of beta-catenin in non-tumoral and neoplastic cells by regulating the balance between signaling and adhesive beta-catenin which is a molecule endowed with a dual function being involved both in cell adhesion and in Wnt signaling pathway [4].

PTPRK dephosphorylates EGFR and thereby regulates EGFR tyrosine phosphorylation and subsequent downstream cellular responses, in primary human keratinocytes [5].

PTPRK regulates CD4+ T cell development through ERK1/2-mediated signaling [6].

References

1. Zondag GC, Koningstein GM, Jiang YP, Sap J, Moolenaar WH, and Gebbink MF. Homophilic interactions mediated by receptor tyrosine phosphatases mu and kappa. A critical role for the novel extracellular MAM domain. J Biol Chem. 1995 Jun 16;270(24):14247-50. DOI:10.1074/jbc.270.24.14247 | PubMed ID:7782276 | HubMed [Zondag95]
2. Sap J, Jiang YP, Friedlander D, Grumet M, and Schlessinger J. Receptor tyrosine phosphatase R-PTP-kappa mediates homophilic binding. Mol Cell Biol. 1994 Jan;14(1):1-9. DOI:10.1128/mcb.14.1.1-9.1994 | PubMed ID:8264577 | HubMed [Sap94]
3. Zhang Y, Siebert R, Matthiesen P, Yang Y, Ha H, and Schlegelberger B. Cytogenetical assignment and physical mapping of the human R-PTP-kappa gene (PTPRK) to the putative tumor suppressor gene region 6q22.2-q22.3. Genomics. 1998 Jul 15;51(2):309-11. DOI:10.1006/geno.1998.5323 | PubMed ID:9722959 | HubMed [Zhang98]
4. Xu Y, Tan LJ, Grachtchouk V, Voorhees JJ, and Fisher GJ. Receptor-type protein-tyrosine phosphatase-kappa regulates epidermal growth factor receptor function. J Biol Chem. 2005 Dec 30;280(52):42694-700. DOI:10.1074/jbc.M507722200 | PubMed ID:16263724 | HubMed [Novellino08]
5. Xu Y, Tan LJ, Grachtchouk V, Voorhees JJ, and Fisher GJ. Receptor-type protein-tyrosine phosphatase-kappa regulates epidermal growth factor receptor function. J Biol Chem. 2005 Dec 30;280(52):42694-700. DOI:10.1074/jbc.M507722200 | PubMed ID:16263724 | HubMed [Xu05]
6. Erdenebayar N, Maekawa Y, Nishida J, Kitamura A, and Yasutomo K. Protein-tyrosine phosphatase-kappa regulates CD4+ T cell development through ERK1/2-mediated signaling. Biochem Biophys Res Commun. 2009 Dec 18;390(3):489-93. DOI:10.1016/j.bbrc.2009.09.117 | PubMed ID:19800317 | HubMed [Erdenebayar09]
7. Yang Y, Gil M, Byun SM, Choi I, Pyun KH, and Ha H. Transforming growth factor-beta1 inhibits human keratinocyte proliferation by upregulation of a receptor-type tyrosine phosphatase R-PTP-kappa gene expression. Biochem Biophys Res Commun. 1996 Nov 21;228(3):807-12. DOI:10.1006/bbrc.1996.1736 | PubMed ID:8941358 | HubMed [Yang96]