Cardiac myosin is a substrate for Zipper-interacting Protein Kinase (ZIPK)

Audrey N. Chang, Guohua Chen, Robert D. Gerard, Kristine E. Kamm, James T. Stull

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Zipper-interacting protein kinase (ZIPK) is a member of the death-associated protein kinase family associated with apoptosis in nonmuscle cells where it phosphorylates myosin regulatory light chain (RLC) to promote membrane blebbing. ZIPK mRNA and protein are abundant in heart tissue and isolated ventricular neonatal rat cardiac myocytes. An unbiased substrate search performed with purified ZIPK on heart homogenates led to the discovery of a prominent 20-kDa protein substrate identified as RLC of ventricular myosin. Biochemical analyses showed ZIPK phosphorylated cardiac RLC at Ser-15 with a Vmax value 2-fold greater than the value for smooth/non-muscle RLC; cardiac RLC is a favorable biochemical substrate. Knockdown of ZIPK in cardiac myocytes by small interfering RNA significantly decreased the extent of RLC Ser-15 phosphorylation. Thus, ZIPK may act as a cardiac RLC kinase and thereby affect contractility.

Original languageEnglish (US)
Pages (from-to)5122-5126
Number of pages5
JournalJournal of Biological Chemistry
Issue number8
StatePublished - Feb 19 2010

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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