A myristoyl/phosphoserine switch controls cAMP-dependent protein kinase association to membranes

Ece C. Gaffarogullari, Larry R. Masterson, Emily E. Metcalfe, Nathaniel J. Traaseth, Erica Balatri, Musa M. Musa, Daniel Mullen, Mark D. Distefano, Gianluigi Veglia

Research output: Contribution to journalArticlepeer-review

Abstract

The cAMP-dependent protein kinase [protein kinase A (PKA)] mediates a myriad of cellular signaling events, and its activity is tightly regulated in both space and time. Among these regulatory mechanisms is N-myristoylation, whose biological role has been elusive. Using a combination of thermodynamics, kinetics, and spectroscopic methods, we analyzed the effects of N-myristoylation and phosphorylation at Ser10 on the interactions of PKA with model membranes. We found that, in the absence of lipids, the myristoyl group is tucked into the hydrophobic binding pocket of the enzyme (myr-in state). Upon association with lipid bilayers, the myristoyl group is extruded and inserts into the hydrocarbon region of the lipid bilayer (myr-out state). NMR data indicate that the enzyme undergoes conformational equilibrium between myr-in and myr-out states, which can be shifted byeither interaction with membranes and/or phosphorylation at Ser10. Our results provide evidence that the membrane binding motif of the myristoylated C-subunit of PKA (PKA-C) steers the enzyme toward lipids independent of its regulatory subunit or an A-kinase anchoring protein, providing an additional mechanism to localize the enzyme near membrane-bound substrates.

Original languageEnglish (US)
Pages (from-to)823-836
Number of pages14
JournalJournal of Molecular Biology
Volume411
Issue number4
DOIs
StatePublished - Aug 26 2011

Keywords

  • N-myristoylation
  • NMR spectroscopy
  • lipid bicelles
  • peripheral membrane proteins
  • protein kinase A

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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