Use this URL to cite or link to this record in EThOS:
Title: The roles of Atg4-dependent LC3B delipidation, SigmaR1 and Climp-63 during mammalian autophagy
Author: Mannack, Lilith
ISNI:       0000 0004 5921 023X
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2015
Availability of Full Text:
Access from EThOS:
Autophagy is a lysosomal degradation pathway conserved from yeast to man, in which a double membrane-bound vesicle (the autophagosome) is assembled to engulf and sequester cytoplasmic material. Autophagy serves a multitude of protective roles in the cell including removal of dysfunctional or redundant macromolecules and organelles, engulfment of pathogens and provision of molecular building blocks upon nutrient deprivation. Autophagy is highly regulated, with more than 30 proteins having been identified in the process. This thesis explores the molecular regulation of amino acid and growth factor starvation-induced autophagosome biogenesis. First, I explored the regulation of autophagosome biogenesis dependency on Atg4 dependent LC3B delipidation. Through a siRNA approach I found that the LC3B puncta formation response upon starvation was surprisingly robust i.e. siRNA depletion of Atg4B has no discernable effect on LC3B puncta numbers. However when using LC3B-mutants impaired in Atg4 binding, I found that LC3B delipidation appears to be involved in regulating autophagosome size and p62 turn-over during starvation. With the aim of identifying a novel autophagy protein involved in the completion of the autophagosome, I conducted a small-scale, targeted siRNA screen for ER and mitochondria resident proteins. From this screen I identified SigmaR1 and Climp-63 as important for the completion of the nascent autophagosome. SigmaR1, which caused the greatest accumulation of incomplete autophagosomes, is a protein that has been implicated in a wide variety of processes, including calcium regulation, ER stress response and lipid transfer. Climp-63 is an ER sheet organising protein. Thus, overall this thesis extends the knowledge of Atg4 dependent delipidation during autophagosome biogenesis and the role of ER and mitochondria- resident proteins during autophagosome formation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available