Coincident regulation of PKCd in human platelets by phosphorylation of Tyr311 and Tyr565 and phospholipase C signalling

KJ Hall, ML Jones, AW Poole

Research output: Contribution to journalArticle (Academic Journal)peer-review

36 Citations (Scopus)

Abstract

PKC (protein kinase C)d plays a complex role in platelets, having effects on both positive and negative signalling functions. It is phosphorylated on tyrosine residues in response to thrombin and collagen, and it has recently been shown that Tyr311 is phosphorylated in response to PAR (protease-activated receptor) 1 and PAR4 receptor activation. In the present study, we show that Tyr311 and Tyr565 are phosphorylated in response to thrombin, and have examined the interplay between phosphorylation and the classical lipid-mediated activation of PKCd. Phosphorylation of both Tyr311 and Tyr565 is dependent on Src kinase and PLC (phospholipase C) activity in response to thrombin. Importantly, direct allosteric activation of PKCd with PMA also induced phosphorylation of Tyr311 and Tyr565, and this was dependent on the activity of Src kinases, but not PLC. Membrane recruitment of PKCd is essential for phosphorylation of this tyrosine residue, but tyrosine phosphorylation is not required for membrane recruitment of PKCd. Both thrombin and PMA induce recruitment of PKCd to the membrane, and for thrombin, this recruitment is a PLC-dependent process. In order to address the functional role of tyrosine residue phosphorylation of PKCd, we demonstrate that phosphorylation can potentiate the activity of the kinase, although phosphorylation does not play a role in membrane recruitment of the kinase. PKCd is therefore regulated in a coincident fashion, PLC-dependent signals recruiting it to the plasma membrane and by phosphorylation on tyrosine residues, potentiating its activity.
Translated title of the contributionCoincident regulation of PKCd in human platelets by phosphorylation of Tyr311 and Tyr565 and phospholipase C signalling
Original languageEnglish
Pages (from-to)501 - 510
Number of pages10
JournalBiochemical Journal
Volume406 (3)
DOIs
Publication statusPublished - Sep 2007

Bibliographical note

Publisher: Portland Press

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