Protein kinase Cε-dependent activation of proline-rich tyrosine kinase 2 in neonatal rat ventricular myocytes

Allison L Bayer, Maria C. Heidkamp, Amy L. Howes, Joan Heller Brown, Kenneth L. Byron, Allen M. Samarel

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Proline-rich tyrosine kinase 2 (PYK2) is a nonreceptor protein tyrosine kinase that links G-protein-coupled receptors to activation of MAPK cascades and cellular growth. In smooth muscle and other cell types, PYK2 activation is dependent on either Ca2+ or protein kinase C (PKC), and we have previously shown that endothelin-1 (ET) activates PYK2 in adult and neonatal rat ventricular myocytes (NRVM). However, ET both alters intracellular Ca 2+ ([Ca2+]i), and activates the novel, Ca 2+-independent PKCs. Therefore, immunoprecipitation and western blotting experiments were used to examine the PKC and Ca2+ dependence of PYK2 activation in NRVM. PYK2 was activated by ET (100 nM; 2-30 min) and phenylephrine (50 μM; 2-30 min), which are both hypertrophic agonists that activate Gq-coupled receptors. Moreover, adenoviral (Adv) -mediated overexpression of constitutively active (ca) Gαq increased PYK2-Y402 phosphorylation as early as 8 h post-infection, as compared to NRVM infected with a control Adv encoding β-galactosidase. caGαq overexpression also induced PKCε and PKCδ (but not PKCα) translocation, followed by downregulation of both novel PKC isoenzymes. Phorbol myristate acetate (PMA; 200 nM), a direct activator of Ca2+-dependent and Ca2+-independent PKCs, activated PYK2 within 10 min, and PYK2 phosphorylation remained elevated after 30 min of stimulation. Adv-mediated overexpression of caPKCε increased PYK2 phosphorylation, whereas Adv-mediated overexpression of a kinase-inactive mutant of PKCε markedly inhibited ET-induced, but not basal PYK2 phosphorylation. In contrast, both basal and ET-induced PYK2 phosphorylation were blocked by treatment with the Src-family protein kinase inhibitor PP2. Although reducing [Ca2+]i with either nifedipine (10 μM) or BAPTA-AM (50 μM) decreased basal PYK2 phosphorylation, it did not prevent ET-induced PYK2 activation. Furthermore, increasing [Ca 2+]i with ionomycin (10 μM), K+ depolarization, or BayK8644 (1 μM) was not sufficient to further activate PYK2. These data demonstrate that ET-induced PYK2 activation is Gq, PKCε, and Src dependent, describing a distinct signaling pathway leading to agonist-induced PYK2 activation in cardiomyocytes.

Original languageEnglish
Pages (from-to)1121-1133
Number of pages13
JournalJournal of Molecular and Cellular Cardiology
Volume35
Issue number9
DOIs
StatePublished - Sep 1 2003
Externally publishedYes

Fingerprint

Focal Adhesion Kinase 2
Muscle Cells
Protein Kinase C
Endothelin-1
Phosphorylation
Gq-G11 GTP-Binding Protein alpha Subunits
Galactosidases

Keywords

  • FAK
  • Heart
  • Hypertrophy
  • PYK2
  • Signal transduction

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

Cite this

Protein kinase Cε-dependent activation of proline-rich tyrosine kinase 2 in neonatal rat ventricular myocytes. / Bayer, Allison L; Heidkamp, Maria C.; Howes, Amy L.; Heller Brown, Joan; Byron, Kenneth L.; Samarel, Allen M.

In: Journal of Molecular and Cellular Cardiology, Vol. 35, No. 9, 01.09.2003, p. 1121-1133.

Research output: Contribution to journalArticle

Bayer, Allison L ; Heidkamp, Maria C. ; Howes, Amy L. ; Heller Brown, Joan ; Byron, Kenneth L. ; Samarel, Allen M. / Protein kinase Cε-dependent activation of proline-rich tyrosine kinase 2 in neonatal rat ventricular myocytes. In: Journal of Molecular and Cellular Cardiology. 2003 ; Vol. 35, No. 9. pp. 1121-1133.
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KW - FAK

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KW - Hypertrophy

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KW - Signal transduction

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