Project Details
Projekt
Redox-control of the active/deactive transition of mitochondrial complex I
Applicant
Professor Dr. Ulrich Brandt
Subject Area
Biochemistry
Term
from 2014 to 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 251961289
Mitochondrial complex I is the largest and most complicated enzyme of the respiratory chain that has been implicated in numerous degenerative disorders and is a major source of reactive oxygen species. Complex I can undergo a reversible so called active/deactive (A/D) transition. It has been shown that nitrosation of a specific cysteine residue that is accessible only the deactive form prevents activation of complex I and may be involved in blocking the respiratory chain under certain pathological conditions. We have assigned this redox control of complex I to a conserved cysteine in the mitochondrially encoded subunit ND3. The first aim of the proposed project is to understand the molecular mechanism of the active/deactive transition of complex I and how it is controlled by modification of the cysteine in subunit ND3. We will use our recently solved X-ray crystallographic structure of mitochondrial complex I that suggests significant structural changes between the A- and D-from of complex I around its cysteine switch, to build structural models of the two states based on Molecular Dynamics simulations. This information will be used to guide a mutagenesis study aimed at identifying the protein domains and residues critically involved in the A/D transition in order to understand the structural changes associated with this process at the atomic level. In a second part of the project we will study how the A/D transition and the associated cysteine switch is controlled depending on the functional state of mitochondria. For this we will develop a quantitative redox-proteomic strategy to address the A/D transition state and the status of the associated cysteine switch in mitochondria and cells. This will provide valuable information to predict and understand the role of the A/D transition and the associated cysteine switch mechanism in health and disease. In the third part of the project we will explore the role of the A/D transition and the associated cysteine switch in mitochondrial disease. For this, we will take advantage of the large collection of cell lines from patients with complex I related mitochondrial diseases available at the Nijmegen Centre for Mitochondrial Disorders. Our studies with patient fibroblasts will provide insight into the involvement of the A/D transition in pathophysiological mechanisms associated with complex I deficiencies and may contribute to understand the origin of the wide range of disease phenotypes typically observed in mitochondrial disorders. This will also provide important clues for the physiological role of the A/D transition in the healthy state. Using our recently developed complexome profiling approach, we will search the mitochondrial inventory of multiprotein complexes for factors regulating the A/D transition to reach out to so far unexplored mechanisms of mitochondrial redox regulation.
DFG Programme
Priority Programmes
International Connection
Netherlands
