High throughput screens for modulators of mitochondrial ATP-dependent proteolysis

Project Details


Mitochondrial ATP-dependent proteases are vital for maintaining cellular homeostasis and the
response to environmental stress. These enzymes are ATP-powered proteolytic machines that
selectively degrade abnormal proteins and regulate metabolic processes. In many disease states
and aging, the increased generation of reactive oxygen species within mitochondria results in
protein oxidation and aggregation. As a counter-measure, the mitochondrial Lon protease for
example, degrades oxidized aconitase thereby preventing its irreversible accumulation and
aggregation. The oxidative damage of proteins, nucleic acids and lipids is directly linked to aging,
heart disease and neuromuscular disorders;whereas protein aggregation is common to many
neurodegenerative disorders. In addition, recent work suggests that Lon-mediated proteolysis may
be important in tumorigenesis and the adaptation of intratumoral cells to hypoxia. Unfortunately,
there are no specific high affinity inhibitors or activators of mitochondrial ATP-dependent
proteases. The goals of this proposal are to develop
assays for identifying and validating compounds that selectively activate or inhibit the Lon
protease. Aim 1 is to develop and optimize a primary screening assay for measuring Lonmediated
degradation of reporter peptide substrate using time-resolved fluorometry. The feasibility and
reproducibility of these assays will be demonstrated using commercially available chemical
libraries. Aim 2 is to develop and optimize secondary- and counter- screening assays, which will
provide information about the mechanism of compound activity, and distinguish compounds that
are Lon-specific from those that target other mitochondrial or non-mitochondrial proteases. Small
molecule activators of mitochondrial ATP-dependent proteolysis have potential application in the
treatment of neurodegenerative and/or myocardial dysfunctions linked to mitochondrial protein
aggregation. Our preliminary data suggest that inhibitors of mitochondrial ATP-dependent
proteolysis may function as anti-cancer agents, with potential clinical application either alone or
in combination with other chemotherapeutic strategies. Taken together, Lon and other
mitochondrial ATP-dependent proteases may be new and viable drug targets.
Effective start/end date8/15/097/31/12


  • National Institute of General Medical Sciences: $373,850.00


  • Medicine(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Clinical Neurology
  • Neurology
  • Cancer Research


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