The interaction of the mitochondrial protein importer TOMM34 with HSP70 is regulated by TOMM34 phosphorylation and binding to 14-3-3 adaptors
| Autor: | Oliver Simoncik, Daniel Kavan, Pavla Vankova, Petr Müller, Petr Man, Filip Trčka, Michal Durech, Borivoj Vojtesek, Veronika Vandová |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
HSP72 Heat-Shock Proteins Plasma protein binding Biochemistry Mitochondrial Membrane Transport Proteins Protein–protein interaction Mitochondrial Proteins 03 medical and health sciences Mitochondrial Precursor Protein Import Complex Proteins Translocase Humans HSP70 Heat-Shock Proteins HSP90 Heat-Shock Proteins Phosphorylation Protein kinase A Molecular Biology 030102 biochemistry & molecular biology biology Chemistry Cell Biology Cyclic AMP-Dependent Protein Kinases Transport protein DNA-Binding Proteins Tetratricopeptide 030104 developmental biology 14-3-3 Proteins Mitochondrial Membranes Protein Structure and Folding biology.protein Biophysics MCF-7 Cells Protein folding Molecular Chaperones Protein Binding Signal Transduction Transcription Factors |
| Zdroj: | J Biol Chem |
| ISSN: | 1083-351X |
| Popis: | Translocase of outer mitochondrial membrane 34 (TOMM34) orchestrates heat shock protein 70 (HSP70)/HSP90–mediated transport of mitochondrial precursor proteins. Here, using in vitro phosphorylation and refolding assays, analytical size-exclusion chromatography, and hydrogen/deuterium exchange MS, we found that TOMM34 associates with 14-3-3 proteins after its phosphorylation by protein kinase A (PKA). PKA preferentially targeted two serine residues in TOMM34: Ser(93) and Ser(160), located in the tetratricopeptide repeat 1 (TPR1) domain and the interdomain linker, respectively. Both of these residues were necessary for efficient 14-3-3 protein binding. We determined that phosphorylation-induced structural changes in TOMM34 are further augmented by binding to 14-3-3, leading to destabilization of TOMM34's secondary structure. We also observed that this interaction with 14-3-3 occludes the TOMM34 interaction interface with ATP-bound HSP70 dimers, which leaves them intact and thereby eliminates an inhibitory effect of TOMM34 on HSP70-mediated refolding in vitro. In contrast, we noted that TOMM34 in complex with 14-3-3 could bind HSP90. Both TOMM34 and 14-3-3 participated in cytosolic precursor protein transport mediated by the coordinated activities of HSP70 and HSP90. Our results provide important insights into how PKA-mediated phosphorylation and 14-3-3 binding regulate the availability of TOMM34 for its interaction with HSP70. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|