Autophagy represents a complex pathway of cellular homeostasis that functions in cytoprotection, but if dysregulated can cause cell death;a complete knowledge of regulation is critical for the potential modulation of this process for therapeutic purposes, and to increase our basic understanding of membrane dynamics and organelle biogenesis. Autophagy occurs in all eukaryotes and the protein components of the autophagic machinery are conserved from yeast to mammals. The hallmark of this process is the formation of double- membrane cytosolic vesicles, autophagosomes that sequester cytoplasmic components. After completion, the autophagosomes fuse with the lysosome/vacuole to release the inner vesicle that is broken down, allowing access to the cargo. Autophagy plays a role in various developmental processes and is associated with a range of pathophysiological conditions. The long-term goal of this proposal is to understand the mechanism and regulation of autophagy and how this translates into autophagosome formation. The molecular field of autophagy is slightly over ten years old, which is startling for a pathway with connections to such a wide range of physiological processes. In a practical sense, this also means there are many questions remaining to be answered. For example, we want to (1) determine how environmental signals are transduced into an autophagic response, defining the kinases, phosphatases and transcription factors that control autophagy;(2) identify the origin of the sequestering vesicle and determine how membrane from a variety of organelles can be commandeered to provide the material needed for autophagosome formation;and (3) understand what regulatory controls determine the switch between specific and non-specific types of autophagy, and the method of achieving cargo specificity. We are using yeast to investigate the molecular mechanism of autophagy;this is the best system for a molecular genetic and biochemical analysis of this complex process. Because of the high degree of conservation, however, the information we learn from yeast will be applicable to higher eukaryotes. At present, over thirty autophagy-related (Atg) proteins have been identified, but their functions and the regulatory processes that control them are largely undefined. The experiments described in this proposal are significant because they will elucidate important links between upstream regulatory components and the machinery that carries out autophagy, providing the next step in a comprehensive analysis that links the signal transduction elements to the functional apparatus, advancing our knowledge of basic cell biology, and identifying targets for ultimate therapeutic intervention. The proposed research is innovative, because it is providing new, and in some cases paradigm-shifting, information about the regulatory and functional components of autophagy.

Public Health Relevance

Autophagy plays a role in normal developmental processes, innate immunity and in determining life span, and its dysfunction has been implicated in a wide range of human diseases including cancer, some types of neurodegeneration, certain bacterial and viral infections, gastrointestinal disorders and heart disease. It may be possible to modulate autophagy for therapeutic purposes, turning it on and off at precise times, and in specific tissues, to prevent or ameliorate the onset of diseases or their symptoms. To use autophagy in this manner, however, will require a complete understanding of its mechanism and regulation.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM053396-24
Application #
8470173
Study Section
Nuclear and Cytoplasmic Structure/Function and Dynamics Study Section (NCSD)
Program Officer
Ainsztein, Alexandra M
Project Start
1991-06-01
Project End
2015-05-31
Budget Start
2013-06-01
Budget End
2014-05-31
Support Year
24
Fiscal Year
2013
Total Cost
$630,431
Indirect Cost
$206,191
Name
University of Michigan Ann Arbor
Department
None
Type
Organized Research Units
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
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Backues, Steven K; Orban, Daniel P; Bernard, Amélie et al. (2015) Atg23 and Atg27 act at the early stages of Atg9 trafficking in S. cerevisiae. Traffic 16:172-90
Bernard, Amelie; Klionsky, Daniel J (2014) Defining the membrane precursor supporting the nucleation of the phagophore. Autophagy 10:1-2
Miller-Fleming, Leonor; Cheong, Heesun; Antas, Pedro et al. (2014) Detection of Saccharomyces cerevisiae Atg13 by western blot. Autophagy 10:514-7
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Jin, Meiyan; Klionsky, Daniel J (2014) Regulation of autophagy: modulation of the size and number of autophagosomes. FEBS Lett 588:2457-63
Klionsky, Daniel J; Thorburn, Andrew (2014) Clinical research and Autophagy. Autophagy 10:1357-8
Klionsky, Daniel J (2014) Coming soon to a journal near you — the updated guidelines for the use and interpretation of assays for monitoring autophagy. Autophagy 10:1691
Popelka, Hana; Uversky, Vladimir N; Klionsky, Daniel J (2014) Identification of Atg3 as an intrinsically disordered polypeptide yields insights into the molecular dynamics of autophagy-related proteins in yeast. Autophagy 10:1093-104
Varga, M; Sass, M; Papp, D et al. (2014) Autophagy is required for zebrafish caudal fin regeneration. Cell Death Differ 21:547-56

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