Selective Phosphorylation Inhibitor of Delta Protein Kinase C-Pyruvate Dehydrogenase Kinase Protein-Protein Interactions: Application for Myocardial Injury in Vivo.

ABSTRACT: Protein kinases regulate numerous cellular processes, including cell growth, metabolism, and cell death. Because the primary sequence and the three-dimensional structure of many kinases are highly similar, the development of selective inhibitors for only one kinase is challenging. Furthermore, many protein kinases are pleiotropic, mediating diverse and sometimes even opposing functions by phosphorylating multiple protein substrates. Here, we set out to develop an inhibitor of a selective protein kinase phosphorylation of only one of its substrates. Focusing on the pleiotropic delta protein kinase C (?PKC), we used a rational approach to identify a distal docking site on ?PKC for its substrate, pyruvate dehydrogenase kinase (PDK). We reasoned that an inhibitor of PDK's docking should selectively inhibit the phosphorylation of only PDK without affecting phosphorylation of the other ?PKC substrates. Our approach identified a selective inhibitor of PDK docking to ?PKC with an in vitro Kd of ?50 nM and reducing cardiac injury IC50 of ?5 nM. This inhibitor, which did not affect the phosphorylation of other ?PKC substrates even at 1 ?M, demonstrated that PDK phosphorylation alone is critical for ?PKC-mediated injury by heart attack. The approach we describe is likely applicable for the identification of other substrate-specific kinase inhibitors.

SUBMITTER: Qvit N 

PROVIDER: S-EPMC5065007 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature