Autophagy is a cellular stress response pathway that controls cell growth and maintains homeostasis. Dysregulation of autophagy leads to several cytopathic disorders, such as cancer, inflammatory bowel disorders, and neurodegeneration. Cellular stress, such as nutrient starvation or infection, triggers the autophagic cascade by activating the ATG16L1/5-12 protein complex, which delivers cellular compartments to lysosomes for degradation. Very little is known about where ATG16L1 is located under nutrient rich conditions and about the first steps of its activation, prior to binding to nascent autophagosome. We discovered three post-translational modifications (PTM’s) of ATG16L1, S268A, S269/287A, and T281A, that occur under nutrient rich conditions and are lost upon starvation. We also discovered under basal conditions ATG16L1 is localized to the cytoskeleton through interaction with SPEC1L, and that ATG16L1/SPEC1L complex dissociates upon activation. We hypothesize that the stress-sensitive PTM’s mediate the complex’s stability; during stress, they dissociate from the ATG16L1/SPEC1L complex leading to the activation of the complex. My objective is to create phospho-mimetic and phospho-dead mutations of ATG16L1 to detect if these phosphorylation events regulate ATG16L1 inactivation at the cytoskeleton. Mutations were inserted into the genome of virus vectors by Site-Directed Mutagenesis, based on KOD Xtreme Hot Start and Pfu Turbo DNA Polymerase enzymes protocols. Salmonella bacteria were infected with the vectors to evaluate the mutations through direct-sequencing. Mutations will be introduced in vitro into mammalian cells, and the results will be analysed by Western Blotting and Immunoprecipitation. Abstract Submission for the Undergraduate Research Opportunity Program (UROP). Research conducted under the supervision of Dr. Ryan Russell.
Poster associated with the Abstract is attached.