Project Grant R35GM154869

MECHANISMS OF CELLULAR MAINTENANCE - ABSTRACT NUMEROUS ANIMAL CELL TYPES HAVE EXTENDED POST-DEVELOPMENTAL LIFESPANS, NECESSITATING ROBUST MECHANISMS FOR CELLULAR MAINTENANCE. CELLULAR MAINTENANCE DETERIORATES IN CONDITIONS LIKE METABOLIC AND NEURODEGENERATIVE DISEASES AND UPON ACUTE OR CHRONIC EXPOSURE TO STRESSORS SUCH AS POLLUTION AND RADIATION. MOREOVER, DECLINE IN CELLULAR MAINTENANCE IS AN EVOLUTIONARILY CONSERVED PATHOLOGY OF AGING. DESPITE ITS SIGNIFICANCE, OUR UNDERSTANDING OF THE FUNDAMENTAL MECHANISMS UNDERPINNING CELLULAR MAINTENANCE REMAINS DEFICIENT. MY LAB AIMS TO ELUCIDATE HOW POST-DEVELOPMENTAL CELLS PRESERVE THEIR INTEGRITY AND FUNCTION IN VIVO. WE USE THE NEMATODE C. ELEGANS FOR ITS POWERFUL GENETIC AND LIVE FLUORESCENT IMAGING CAPABILITIES, AND FOR ITS SUITABILITY FOR STUDYING CELL BIOLOGY WITHIN THE ORGANISM'S PHYSIOLOGICAL CONTEXT. IN THE NEXT FIVE YEARS, WE PROPOSE TO INVESTIGATE TWO KEY ASPECTS OF CELLULAR MAINTENANCE: FIRST, WITHIN MATURE CELLS, PROTEINS AND ORGANELLES UNDERGO CONTINUOUS TURNOVER: THEY ARE DEGRADED, LARGELY BY LYSOSOMES, AND REPLACED TO ENSURE CELLULAR QUALITY. THE MECHANISMS DETERMINING LYSOSOMAL DEGRADATIVE CAPACITY AND CONTROLLING THE RATE AT WHICH DEGRADATIVE CARGOES ARE SENT TO THE LYSOSOME DURING STEADY-STATE MAINTENANCE ARE NOT WELL UNDERSTOOD. BUILDING ON RESEARCH INITIATED IN MY INDEPENDENT LAB, WE WILL TAKE A THREE-PRONGED STRATEGY TO ADDRESS THIS GAP IN KNOWLEDGE, THAT WILL: PROBE THE CONTROL MECHANISMS OF AN ESTABLISHED REGULATOR OF DEGRADATIVE CAPACITY, DISCOVER NOVEL REGULATORS OF DEGRADATIVE CAPACITY THROUGH AN UNBIASED GENETIC SCREEN, AND DEVELOP A NEW TOOL TO MEASURE HOMEOSTATIC PROTEIN DEGRADATION, AN INDICATOR OF DEGRADATIVE FLUX, WITH HIGH SPATIAL RESOLUTION IN VIVO. AT PRESENT, EFFECTIVE METHODS TO MEASURE THIS REMAIN ELUSIVE; THE DEVELOPMENT OF THIS TOOL WILL NOT ONLY ENABLE THE EXPERIMENTAL INTERROGATION OF LYSOSOMAL DEGRADATIVE FLUX BUT ALSO FACILITATE EXPLORATION OF NUMEROUS OTHER CELL BIOLOGY QUESTIONS. SECOND, CELLULAR MAINTENANCE IS NOT FULLY CELL-INTRINSIC; RATHER, IT IS GOVERNED BY INTRICATE INTERCELLULAR SIGNALING THAT COORDINATES BOTH MAINTENANCE AND METABOLISM ACROSS DIVERSE CELL TYPES WITHIN AN ANIMAL. THE MOLECULAR MECHANISMS UNDERPINNING THIS COORDINATION ARE INCOMPLETELY UNDERSTOOD. DURING MY POSTDOCTORAL RESEARCH, I DEVELOPED THE DAUER - A C. ELEGANS ALTERNATE ORGANISMAL STATE - AS AN EXPERIMENTAL PARADIGM TO STUDY HOW CELLULAR MAINTENANCE CAN BE DRAMATICALLY EXTENDED VIA INTRACELLULAR METABOLIC SIGNALING. WE WILL EXPAND ON THIS LINE OF RESEARCH TO DISCOVER NEW UNDERSTANDINGS OF THE INTERPLAY BETWEEN CELLULAR MAINTENANCE, ORGANISMAL METABOLISM, AND METABOLIC SIGNALING. COLLECTIVELY, THIS RESEARCH WILL BRIDGE EXISTING GAPS IN OUR UNDERSTANDING OF THE INTRACELLULAR AND EXTRACELLULAR MECHANISMS OF CELL MAINTENANCE, LAYING THE FOUNDATION FOR DESIGNING INTERVENTIONS AGAINST CELLULAR MAINTENANCE LOSS IN DISEASE AND AGING.