Phosphatase Subfamily PTPRK

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

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