TY - JOUR
T1 - A myristoyl/phosphoserine switch controls cAMP-dependent protein kinase association to membranes
AU - Gaffarogullari, Ece C.
AU - Masterson, Larry R.
AU - Metcalfe, Emily E.
AU - Traaseth, Nathaniel J.
AU - Balatri, Erica
AU - Musa, Musa M.
AU - Mullen, Daniel
AU - Distefano, Mark D.
AU - Veglia, Gianluigi
PY - 2011/8/26
Y1 - 2011/8/26
N2 - 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.
AB - 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.
KW - N-myristoylation
KW - NMR spectroscopy
KW - lipid bicelles
KW - peripheral membrane proteins
KW - protein kinase A
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U2 - 10.1016/j.jmb.2011.06.034
DO - 10.1016/j.jmb.2011.06.034
M3 - Article
C2 - 21740913
AN - SCOPUS:80051666683
VL - 411
SP - 823
EP - 836
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
SN - 0022-2836
IS - 4
ER -