Doctoral position - Understanding the unique features of the mitochondrial Hsp70 system that mediate translocation and folding of proteins

Department/Institute: LMU Faculty of Biology, Department of Cell Biology

Subject areas/Research fields: Cell Biology, Biochemistry

Keywords: mitochondria, Hsp70 chaperones, protein import, protein folding

Name of supervisor: Dr. Dejana Mokranjac

Project title: Understanding the unique features of the mitochondrial Hsp70 system that mediate translocation and folding of proteins

Project description:

Hsp70 chaperones are a conserved family of molecular chaperones involved in a plethora of cellular processes ranging from folding of newly synthesized proteins and prevention of their aggregation over translocation of proteins across cellular membranes and assembly/disassembly of protein complexes to protein degradation. All these diverse functions of Hsp70s rely on their ability to reversibly bind to substrate proteins via their C-terminal domain in a reaction regulated by the nucleotide bound to their N-terminal domain. Progression through the ATP hydrolysis driven cycles of Hsp70 chaperones is typically regulated by two types of co-chaperones, J-proteins that stimulate the ATPase activity of Hsp70s and nucleotide-exchange factors that release ADP molecules and thereby enable binding of a new molecule of ATP. In mitochondria, a member of the Hsp70 family, mitochondrial Hsp70, plays an essential role in translocation of proteins across two mitochondrial membranes and in subsequent folding of proteins. MtHsp70 is a peculiar member of the Hsp70 family as its function requires help of cochaperones not present elsewhere. First, mtHsp70 is recruited to the translocation site by Tim44, a peripheral membrane protein. Second, a J-protein is not sufficient for the stimulation of the ATPase activity of mtHsp70 during translocation of proteins but rather a complex of a J- and a J-like protein is required. Third, mtHsp70 is itself an aggregation-prone protein and its aggregation is prevented by a dedicated chaperone Hep1. 

We love proteins and we love yeast so here, we will combine biochemistry with yeast genetics and cell biology in order to obtain molecular understanding of these unique features of the mtHsp70 system that mediate translocation and folding of proteins. 

References: Mokranjac D. (2020) How to get to the other side of the mitochondrial inner membrane – the protein import motor. Biol. Chem. 401(6-7):723-736

For further information, please contact: Dr. Dejana Mokranjac, e-mail: mokranjac@bio.lmu.de

Reseach group website: https://www.cellbiology.bio.lmu.de/research_groups/mokranjac/index.html

Apply: Please send your application through the online portal of the Graduate School Life Science Munich (LSM)