Molecular and Cellular Biochemistry

, Volume 97, Issue 1, pp 87–98

Phosphorylation of smooth muscle myosin by type II Ca2+/calmodulin-dependent protein kinase

  • Arthur M. Edelman
  • Wei-Hsung Lin
  • Donna J. Osterhout
  • Mark K. Bennett
  • Mary B. Kennedy
  • Edwin G. Krebs
Original Article

DOI: 10.1007/BF00231704

Cite this article as:
Edelman, A.M., Lin, W., Osterhout, D.J. et al. Mol Cell Biochem (1990) 97: 87. doi:10.1007/BF00231704

Abstract

Brain type II Ca2+/calmodulin-dependent protein kinase was found to phoshorylate smooth muscle myosin, incorporating maximally ∼ 2 mol of phosphoryl per mol of myosin, exclusively on the 20,000 dalton light chain subunit. After maximal phosphorylation of myosin or the isolated 20,000 dalton light chain subunit by myosin light chain kinase, the addition of type II Ca2+/calmodulin-dependent protein kinase led to no further incorporation indicating the two kinases phosphorylated a common site. This conclusion was supported by two dimensional mapping of tryptic digests of myosin phosphorylated by the two kinases. By phosphoamino acid analysis the phosphorylated residue was identified as a serine. The phosphorylation by type II Ca 2+/calmodulin-dependent protein kinase of myosin resulted in enhancement of its actin-activated Mg2+-ATPase activity. Taken together, these data strongly support the conclusion that type II Ca2+/calmodulin-dependent protein kinase phosphorylates the same amino acid residue on the 20,000 dalton light chain subunit of smooth muscle myosin as is phosphorylated by myosin light chain kinase and suggest an alternative mechanism for the regulation of actin-myosin interaction.

Key words

myosincalciumcalmodulintype II kinase

Abbreviations

SDS-PAGE

Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis

EGTA

Ethylene Glycol Bis (β-amino-ethyl ether)-N,N,N′,N′-Tetraacetic Acid

DTT

Dithiothreitol

LC20

Gizzard Smooth Muscle Phosphorylatable 20 kDa Myosin Light Chain

LC17

Gizzard Smooth Muscle, 17 kDa Myosin Light Chain

H Chain

Gizzard Smooth Muscle 200 kDa Myosin Heavy Chain

TPCK

L-1-Tosylamido-2-Phenylethyl Chloromethyl Ketone

MOPS

3-(N-morpholino) Propanesulfonic Acid

Copyright information

© Kluwer Academic Publishers 1990

Authors and Affiliations

  • Arthur M. Edelman
    • 1
  • Wei-Hsung Lin
    • 1
  • Donna J. Osterhout
    • 1
  • Mark K. Bennett
    • 2
  • Mary B. Kennedy
    • 3
  • Edwin G. Krebs
    • 3
  1. 1.Department of Pharmacology and Therapeutics, School of Medicine and Biomedical SciencesState University of New York at BuffaloBuffaloUSA
  2. 2.Division of Biology, 216-76California Institute of TechnologyPasadenaUSA
  3. 3.Howard Hughes Medical InstituteUniversity of WashingtonSeattleUSA