Project SummaryThe aging population and coincident rise in associated diseases demand a better understanding of the basicmechanisms of aging to design appropriate interventions and prolong human health. Elucidating the molecularmechanisms of the processes that slow aging, such as lifespan extension by caloric or dietary restriction,would provide prime candidates for therapeutic intervention. Model organisms have allowed major advancesin defining aging mechanisms due to their exceptionally powerful genetics and analytical tools, and becausethese processes are evolutionarily conserved from humans to yeasts. We discovered a new pathway inSchizosaccharomyces pombe that both regulates autophagy and extends lifespan. Autophagy is a processthat degrades and recycles proteins and organelles, and has been linked to lifespan and diseases associatedwith human aging. We found that both autophagy and lifespan are regulated through the cyclin-dependentkinase Pef1, an ortholog of human Cdk5. Pef1 acts with its cyclin Clg1 to limit lifespan and autophagy, and isopposed by the effector kinase Cek1 that extends lifespan and increases autophagy levels. The Clg1-Pef1-Cek1 pathway acts independently of TOR, the only other pathway known to regulate both lifespan andautophagy, but how these processes are controlled by the Pef1 pathway is unknown. Aim 1 will test thehypothesis that the Pef1 pathway senses nutrients to control lifespan and autophagy. This aim will besignificant for testing the linkage between autophagy and lifespan extension by caloric or dietary restriction.Establishing the mechanism by which the Pef1 pathway regulates lifespan and autophagy requires knowingthe downstream effectors, and Aim 2 describes a novel chemical genomics approach to identify Pef1 targets.We modified the Pef1 kinase to allow selective binding of ATP analogs that tag kinase substrates to allow theirisolation, and used the Pef1 variant to identify the substrates. We identified substrates with predicted roles inautophagy and lifespan, as well as substrates that we hypothesize mediate Pef1 control through signalingpathways. Aim 2 will validate the substrates and identify substrates of the effector kinase Cek1. Aim 3 willdetermine how the phosphorylation of Pef1 and Cek1 substrates affects specific processes in lifespan andautophagy control, and will also use high-throughput functional characterization of substrates to revealsignaling pathways regulated by the Pef1 pathway. The strong functional homology between Pef1 and humanCdk5 indicates that the Clg1-Pef1-Cek1 pathway, its substrates and functions will be conserved in humans,which we will also test in Aim 3. The results of these proposed studies will provide a mechanistic frameworkfor a new, conserved lifespan and autophagy-regulating pathway with important ramifications for healthyhuman aging.
|Effective start/end date||5/1/16 → 4/30/21|
- National Institutes of Health: $324,925.00