Medicine and Health Sciences Commons^™

Mitophagy-Mediated Regulation Of Ros Homeostasis During Hsc Activation Contributes To Cell Fate, Amber Lynne Smith

Theses and Dissertations (ETD)

The ability of hematopoietic stem cells to self-renew and differentiate is required for the maintenance of all blood lineages under basal physiologic conditions and in response to inflammatory stress. The degradative capacity of the autophagy-lysosomal system is a determinant of hematopoietic stem cell (HSC) activation status with low autophagy predicting activation of HSCs, and autophagy deficiency causing the spontaneous loss of quiescence and HSC exhaustion. Although an increase in mitochondrial activity has been suggested as the cause of HSC depletion in autophagy-defective models, the contribution of mitophagy to HSC function remains to be elucidated. Here, we capitalized on the observation …

Biochemical And Structural Characterization Of The Atg8/Lc3 Lipidation Pathway, Yumei Zheng

Theses and Dissertations (ETD)

Atg8 and its eukaryotic orthologues LC3 and GARBARAP family proteins (referred here to Atg8 family proteins) play crucial roles in autophagy through their covalent ligation to lipids, typically phosphatidylethanolamine (PE), in a process known as lipidation. Lipidation of Atg8 family proteins regulates numerous facets of the autophagy process, including regulating expansion of the phagophore membrane, recruiting selected cargoes for degradation, and providing an autophagosome membrane-bound platform mediating dynamic interactions with other regulatory proteins. Atg8 family proteins are ubiquitin-like proteins (UBLs), and their lipidation involves a divergent UBL conjugation cascade including Atg7, Atg3, and Atg12–Atg5-Atg16 acting as E1, E2, and E3 …

Novel Insights Into Ubiquitin-Like Protein E1-E2 Interactions, Asad Taherbhoy

Theses and Dissertations (ETD)

Posttranslational modification of macromolecules by ubiquitin-like proteins (UBLs) such as ubiquitin, Sumo and NEDD8 regulate a vast array of processes in the cell. Transfer of UBLs to their target generally occurs by a series of molecular handoffs down an E1‑E2‑E3 cascade. We are interested in understanding how E1‑E2 pairs interact and mediate UBL transfer. To this effect, we studied two E1‑E2 pairs: the Sumo pathway (Sumo utilizes a canonical E1 and E2) and the Atg8 pathway (Atg8 is a UBL involved in autophagy that utilizes a non-canonical E1‑E2 pair).

Sumo conjugation is initiated by the heterodimeric Aos1‑Uba2 E1 enzyme (in …