Resolving the conformational dynamics of large multidomain proteins has proven to be a significant challenge. Here we use a variety of techniques to dissect the roles of individual protein kinase Cα (PKCα) regulatory domains in maintaining catalytic autoinhibition. We find that whereas the pseudosubstrate domain is necessary for autoinhibition it is not sufficient. Instead, each regulatory domain (C1a, C1b, and C2) appears to strengthen the pseudosubstrate-catalytic domain interaction in a nucleotide-dependent manner. The pseudosubstrate and C1a domains, however, are minimally essential for maintaining the inactivated state. Furthermore, disrupting known interactions between the C1a and other regulatory domains releases the autoinhibited interaction and increases basal activity. Modulating this interaction between the catalytic and regulatory domains reveals a direct correlation between autoinhibition and membrane translocation following PKC activation.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Biological Chemistry|
|State||Published - Feb 17 2017|
Bibliographical noteFunding Information:
This work was supported in part by American Heart Association Scientist Development Grant 13SDG14270009 and National Institutes of Health Grants 1DP2 CA186752-01 and 1-R01-GM-105646-01-A1 (to S. S.). The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. For cell translocation assays, work was done using the Nikon A1Rsi confocal fluorescence microscope at the University of Minnesota, University Imaging Centers. Time-resolved fluorescence decay measurements were taken at the Biophysical Technology Center at the University of Minnesota.
© 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
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Nikon A1RSI Confocal with SIM Super ResolutionUniversity Imaging Centers
University Imaging Centers
Mark A Sanders (Program Director) & Guillermo Marques (Scientific Director)University Imaging Centers