An Isoform-Specific Myristylation Switch Targets Type II PKA Holoenzymes to Membranes.
Cyclic AMP-dependent protein kinase (PKA) is regulated in part by N-terminal myristylation of its catalytic (C) subunit. Structural information about the role of myristylation in membrane targeting of PKA has been limited. In mammalian cells there are four functionally non-redundant PKA regulatory subunits (RIα, RIβ, RIIα, and RIIβ). PKA is assembled as an inactive R2C2 holoenzyme in cells. To explore the role of N-myristylation in membrane targeting of PKA holoenzymes, we solved crystal structures of RIα:myrC and RIIβ2:myrC2, and showed that the N-terminal myristylation site in the myrC serves as a flexible "switch" that can potentially be mobilized for membrane anchoring of RII, but not RI, holoenzymes. Furthermore, we synthesized nanodiscs and showed by electron microscopy that membrane targeting through the myristic acid is specific for the RII holoenzyme. This membrane-anchoring myristylation switch is independent of A Kinase Anchoring Proteins (AKAPs) that target PKA to membranes by other mechanisms.
Department of Pharmacology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0654, USA.
Ping
P
Zhang
Department of Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0654, USA.
Feng
F
Ye
Department of Pharmacology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0654, USA; Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0654, USA.
Adam C
AC
Bastidas
Department of Pharmacology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0654, USA.
Alexandr P
AP
Kornev
Department of Pharmacology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0654, USA.
Jian
J
Wu
Department of Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0654, USA.
Mark H
MH
Ginsberg
Department of Pharmacology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0654, USA; Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0654, USA. Electronic address: staylor@ucsd.edu.
Susan S
SS
Taylor
D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D054757:Cyclic AMP-Dependent Protein Kinase RIIbeta Subunit / Q000737:chemistry* / Q000378:metabolism*; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit / Q000737:chemistry* / Q000378:metabolism*; D020035:Holoenzymes / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D019814:Myristic Acid / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary
D054757:Cyclic AMP-Dependent Protein Kinase RIIbeta Subunit; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D020035:Holoenzymes; D020033:Protein Isoforms; D019814:Myristic Acid