Co-chaperones containing tetratricopeptide repeat (TPR) domains enable cooperation between Hsp70 and Hsp90 to maintain cellular proteostasis. Although the details of the molecular interactions between some TPR domains and heat shock proteins are known, we describe a novel mechanism by which Tomm34 interacts with and coordinates Hsp70 activities. In contrast to the previously defined Hsp70/Hsp90-organizing protein (Hop), Tomm34 interaction is dependent on the Hsp70 chaperone cycle. Tomm34 binds Hsp70 in a complex process; anchorage of the Hsp70 C terminus by the TPR1 domain is accompanied by additional contacts formed exclusively in the ATP-bound state of Hsp70 resulting in a high affinity entropically driven interaction. Tomm34 induces structural changes in determinants within the Hsp70-lid subdomain and modulates Hsp70/Hsp40-mediated refolding and Hsp40-stimulated Hsp70 ATPase activity. Because Tomm34 recruits Hsp90 through its TPR2 domain, we propose a model in which Tomm34 enables Hsp70/Hsp90 scaffolding and influences the Hsp70 chaperone cycle, providing an additional role for co-chaperones that contain multiple TPR domains in regulating protein homeostasis.

• MeSH
• adenosintrifosfát metabolismus   MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• molekulární modely MeSH
• mutace MeSH
• proteiny tepelného šoku HSP70 chemie   metabolismus   MeSH
• sbalování proteinů MeSH
• simulace molekulového dockingu MeSH
• terciární struktura proteinů MeSH
• transportní proteiny mitochondriální membrány chemie   genetika   metabolismus   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

CHIP is a tetratricopeptide repeat (TPR) 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 CHIP's dynamic conformation and activity. Biochemical, biophysical and modeling 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.

• MeSH
• alosterická regulace MeSH
• exprese genu MeSH
• interferonový regulační faktor 1 genetika   metabolismus   MeSH
• kinetika MeSH
• lidé MeSH
• lymfocyty cytologie   metabolismus   MeSH
• mapování interakce mezi proteiny MeSH
• molekulární modely MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• proteasomový endopeptidasový komplex metabolismus   MeSH
• proteiny tepelného šoku HSP70 chemie   genetika   metabolismus   MeSH
• sekundární struktura proteinů MeSH
• terciární struktura proteinů MeSH
• ubikvitinace MeSH
• ubikvitinligasy chemie   genetika   metabolismus   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH