PMID: 29642029

Authors:

Yang Y, Shu C, Li P, Igumenova TI

Title:

Structural Basis of Protein Kinase Calpha Regulation by the C-Terminal Tail.

Journal:

Biophys J. 2018 Apr 10;114(7):1590-1603. doi: 10.1016/j.bpj.2017.12.030.

Abstract:

Protein kinase C (PKC) isoenzymes are multi-modular proteins activated at the membrane surface to regulate signal transduction processes. When activated by second messengers, PKC undergoes a drastic conformational and spatial transition from the inactive cytosolic state to the activated membrane-bound state. The complete structure of either state of PKC remains elusive. We demonstrate, using NMR spectroscopy, that the isolated Ca(2+)-sensing membrane-binding C2 domain of the conventional PKCalpha interacts with a conserved hydrophobic motif of the kinase C-terminal region, and we report a structural model of the complex. Our data suggest that the C-terminal region plays a dual role in regulating the PKC activity: activating, through sensitization of PKC to intracellular Ca(2+) oscillations; and auto-inhibitory, through its interaction with a conserved positively charged region of the C2 domain.