Alcohol binding in the C1 (C1A+C1B) domain of protein kinase C epsilon.

ABSTRACT: Alcohol regulates the expression and function of protein kinase C epsilon (PKC?). In a previous study we identified an alcohol binding site in the C1B, one of the twin C1 subdomains of PKC? (Das et al., Biochem. J., 421, 405-13, 2009).In this study, we investigated alcohol binding in the entire C1 domain (combined C1A and C1B) of PKC?. Fluorescent phorbol ester, SAPD and fluorescent diacylglycerol (DAG) analog, dansyl-DAG were used to study the effect of ethanol, butanol, and octanol on the ligand binding using fluorescence resonance energy transfer (FRET). To identify alcohol binding site(s), PKC?C1 was photolabeled with 3-azibutanol and 3-azioctanol, and analyzed by mass spectrometry. The effects of alcohols and the azialcohols on PKC? were studied in NG108-15 cells.In the presence of alcohol, SAPD and dansyl-DAG showed different extent of FRET, indicating differential effects of alcohol on the C1A and C1B subdomains. Effects of alcohols and azialcohols on PKC? in NG108-15 cells were comparable. Azialcohols labeled Tyr-176 of C1A and Tyr-250 of C1B. Inspection of the model structure of PKC?C1 reveals that these residues are 40Å apart from each other indicating that these residues form two different alcohol binding sites.The present results provide evidence for the presence of multiple alcohol-binding sites on PKC? and underscore the importance of targeting this PKC isoform in developing alcohol antagonists.

SUBMITTER: Pany S 

PROVIDER: S-EPMC4586410 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature