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

Characteristically for a regulatory protein, the IRF-1 tumor suppressor turns over rapidly with a half-life of between 20-40 min. This allows IRF-1 to reach new steady state protein levels swiftly in response to changing environmental conditions. Whereas CHIP (C terminus of Hsc70-interacting protein), appears to chaperone IRF-1 in unstressed cells, formation of a stable IRF-1CHIP complex is seen under specific stress conditions. Complex formation, in heat- or heavy metal-treated cells, is accompanied by a decrease in IRF-1 steady state levels and an increase in IRF-1 ubiquitination. CHIP binds directly to an intrinsically disordered domain in the central region of IRF-1 (residues 106-140), and this site is sufficient to form a stable complex with CHIP in cells and to compete in trans with full-length IRF-1, leading to a reduction in its ubiquitination. The study reveals a complex relationship between CHIP and IRF-1 and highlights the role that direct binding or "docking" of CHIP to its substrate(s) can play in its mechanism of action as an E3 ligase.

• MeSH
• aminokyselinové motivy MeSH
• interferonový regulační faktor 1 * chemie   metabolismus   MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• nádorové buněčné linie MeSH
• nádorové supresorové proteiny * chemie   metabolismus   MeSH
• peptidové fragmenty metabolismus   MeSH
• proteiny tepelného šoku HSP70 metabolismus   MeSH
• reakce na tepelný šok MeSH
• sekvence aminokyselin MeSH
• terciární struktura proteinů MeSH
• těžké kovy toxicita   MeSH
• ubikvitin konjugující enzymy metabolismus   MeSH
• ubikvitinace * účinky léků   MeSH
• ubikvitinligasy * metabolismus   MeSH
• vazba proteinů účinky léků   MeSH
• Check Tag
• lidé MeSH