Ca2+/S100 proteins act as upstream regulators of the chaperone-associated ubiquitin ligase chip (c terminus of hsc70-interacting protein)

Abstract

Background: CHIP is a U-box E3 ubiquitin ligase that facilitates the proteasomal degradation of many client proteins. Results: Ca2+/S100 proteins directly interact with CHIP and suppress the ubiquitination and degradation of the client proteins. Conclusion: We have identified S100 proteins as novel Ca2+-dependent regulators of the CHIP-proteasome pathway. Significance: This is the first indication that S100 proteins form a link between Ca2+ signal transduction and the CHIPproteasome pathway. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.