Protein–Protein Interactions Modulate the Docking-Dependent E3-Ubiquitin Ligase Activity of Carboxy-Terminus of Hsc70-Interacting Protein (CHIP)

Vikram Narayan, Vivien Landre, Jia Ning, Lenka Hernychova, Petr Muller, Chandra Verma, Malcolm D. Walkinshaw, Elizabeth A. Blackburn, Kathryn L. Ball

Research output: Contribution to journalArticlepeer-review

Abstract

CHIP is a tetratricopeptide repeats (TPRs) domain protein that functions as an E3-ubiquitin ligase. As well as linking the molecular chaperones to the ubiquitin proteasome system, CHIP also has a docking-dependent mode where it ubiquitinates native substrates, thereby regulating their steady state levels and/or function. Here we explore the effect of Hsp70 on the docking-dependent E3-ligase activity of CHIP. The TPR-domain is revealed as a binding site for allosteric modulators involved in determining the dynamic conformation and activity of CHIP. Biochemical, biophysical and modelling evidence demonstrate that Hsp70-binding to the TPR, or Hsp70-mimetic mutations, regulate CHIP-mediated ubiquitination of p53 and IRF-1 through effects on U-box activity and substrate binding. HDX-MS was used to establish that conformational-inhibition-signals extended from the TPR-domain to the U-box. This underscores inter-domain allosteric regulation of CHIP by the core molecular chaperones. Defining the chaperone-associated TPR-domain of CHIP as a manager of inter-domain communication highlights the potential for scaffolding modules to regulate, as well as assemble, complexes that are fundamental to protein homeostatic control.

Original languageEnglish
Pages (from-to)2973-2987
JournalMolecular & Cellular Proteomics (MCP)
Volume14
Issue number11
DOIs
Publication statusPublished - 1 Sep 2015

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