Oxidative protein folding in the mitochondrial intermembrane space of parasitic protists

• Applicant: Professor Dr. Marcel Deponte
• Subject Area: Biochemistry
• Term: since 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 259182840

The discovery of the redox proteins Mia40/CHCHD4 and Erv1/ALR, as well as the elucidation of their relevance for oxidative protein folding in the mitochondrial intermembrane space (IMS) of yeast and mammals, founded a new research topic in redox biology and mitochondrial biogenesis. The lack of Mia40/CHCHD4 in a variety of protist lineages raises fundamental and controversial questions regarding the conservation and evolution of this essential process. Do protist Erv homologues act alone or do they use a Mia40 replacement for oxidative protein folding? Furthermore, is it possible to exploit differences between the essential protein import machineries of optisthokonts and parasitic protists for future intervention strategies? The main objective during the current funding period is to clarify whether a one-component or two-component system is required for oxidative protein folding in the IMS of the model organism Leishmania tarentolae and related (pathogenic) eukaryotes. Which protein replaces Mia40 in these organisms? Or are IMS substrate proteins directly oxidized by Erv homologues? We will address these questions in three different work packages in L. tarentolae and baker’s yeast. We will (i) analyze the physiological function of the kinetoplastida-specific second (KISS) domain of LtErv including its possible role as a chaperone for IMS substrate proteins under heat stress, (ii) complete our comparison of substrate and LtErv interactomes to identify suitable Mia40-replacement candidates, and (iii) complete the analysis and validation of the best candidates including a CRISPR-Cas9 screen in L. tarentolae and a functional viability screen for LtErv/Mia40-replacement candidate couples in yeast.

• DFG Programme: Research Grants