Structural basis of conformational variance in phosphorylated and non-phosphorylated states of PKCβII

PKC beta II activation is achieved by primary phosphorylation at three phosphorylation sites, followed by the addition of secondary messengers for full activation. Phosphorylation is essential for enzyme maturation, and the associated conformational changes are known to modulate the enzyme activation. To probe into the structural basis of conformational changes on phosphorylation of PKCII, a comprehensive study of the changes in its complexes with ATP and ruboxistaurin was performed. ATP is a phosphorylating agent in its phosphorylation reaction, and ruboxistaurin is its specific inhibitor. This study provides insight into the differences in the important structural features in phosphorylated and non-phosphorylated states of PKCII. Less conformational changes when PKCII is bound to inhibitor in comparison to when it is bound to its phosphorylating agent in both states were observed. The interactions of ruboxistaurin significant in restricting PKCII to attain the conformational state competent for full activation are reported. Proteins 2014; 82:1332-1347. (c) 2013 Wiley Periodicals, Inc.