title: The C2 Domain and Altered ATP-Binding Loop Phosphorylation at Ser³⁵⁹ Mediate the Redox-Dependent Increase in Protein Kinase C-δ Activity.
abstract: The diverse roles of protein kinase C-δ (PKCδ) in cellular growth, survival, and injury have been attributed to stimulus-specific differences in PKCδ signaling responses. PKCδ exerts membrane-delimited actions in cells activated by agonists that stimulate phosphoinositide hydrolysis. PKCδ is released from membranes as a Tyr(313)-phosphorylated enzyme that displays a high level of lipid-independent activity and altered substrate specificity during oxidative stress. This study identifies an interaction between PKCδ's Tyr(313)-phosphorylated hinge region and its phosphotyrosine-binding C2 domain that controls PKCδ's enzymology indirectly by decreasing phosphorylation in the kinase domain ATP-positioning loop at Ser(359). We show that wild-type (WT) PKCδ displays a strong preference for substrates with serine as the phosphoacceptor residue at the active site when it harbors phosphomimetic or bulky substitutions at Ser(359.) In contrast, PKCδ-S359A displays lipid-independent activity toward substrates with either a serine or threonine as the phosphoacceptor residue. Additional studies in cardiomyocytes show that oxidative stress decreases Ser(359) phosphorylation on native PKCδ and that PKCδ-S359A overexpression increases basal levels of phosphorylation on substrates with both phosphoacceptor site serine and threonine residues. Collectively, these studies identify a C2 domain-pTyr(313) docking interaction that controls ATP-positioning loop phosphorylation as a novel, dynamically regulated, and physiologically relevant structural determinant of PKCδ catalytic activity.
authors.affiliation: Department of Pharmacology, Columbia University, New York, New York, USA.
authors.forename: Jianli
authors.initials: J
authors.lastname: Gong
authors.affiliation: Department of Pharmacology, Columbia University, New York, New York, USA.
authors.forename: Yongneng
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
authors.forename: Pingbo
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Cell and Developmental Biology and Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Barath
authors.initials: B
authors.lastname: Udayasuryan
authors.affiliation: Department of Pharmacology, Columbia University, New York, New York, USA.
authors.forename: Elena V
authors.initials: EV
authors.lastname: Komissarova
authors.affiliation: University of California, San Diego, School of Medicine, La Jolla, California, USA.
authors.forename: Ju
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Cell and Developmental Biology and Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Sivaraj
authors.initials: S
authors.lastname: Sivaramakrishnan
authors.affiliation: Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Van Eyk
authors.affiliation: Department of Pharmacology, Columbia University, New York, New York, USA sfs1@columbia.edu.
authors.forename: Susan F
authors.initials: SF
authors.lastname: Steinberg
mesh_terms: D000818:Animals; D020134:Catalytic Domain; D057809:HEK293 Cells; D006801:Humans; D062105:Molecular Docking Simulation; D032383:Myocytes, Cardiac / Q000201:enzymology*; D018384:Oxidative Stress; D010766:Phosphorylation; D051745:Protein Kinase C-delta / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012694:Serine / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D012694:Serine; C497260:Prkcd protein, rat; D051745:Protein Kinase C-delta