Lecture 13 Flashcards
What is autophagy?
An important degradation pathway to eliminate degraded organelles (e.g., mitochondria) and materials
- Important for cell renewal and organ homeostasis
What do autophagosomes do when autophagy is induced?
Autophagosomes containing double membranes fuse with lysosomes
- Little is known on how this process is regulated, including the initiation of autophagosome formation
How many ATG (autophagy-related) genes have been identified?
32
Where are defects in autophagy seen?
Cancer and neurodegenerative diseases
What are the types of autophagy?
Nonselective and selective
What is nonselective autophagy?
Bulk of cytoplasm is engulfed by autophagosomes (e.g., starvation/fasting conditions)
What is selective autophagy?
Less cytoplasm but contains organelles and cell material that is defective (e.g., ER, ribosomes, peroxisomes, and mitochondria)
Where have most autophagy studies been conducted?
In animals or cell culture
What does exercise/resistance do?
Increases autophagy rates, mitochondrial number, and blocks sarcopenia (muscle loss)
What are the autophagy stages?
1) Induction of autophagy
2) Nucleation, elongation, and assembly of autophagosome (phagophore)
3) Loading of the autophagosome with cellular materials/organelles
4) Docking and fusion of autophagosomes with lysosome - autolysosome
5) Degradation and release of materials into cytoplasm
How does BAG6/BAT3 modulate autophagy?
By affecting EP300/p300 intracellular localization
What autophagy rates play roles in a variety of diseases?
Low
How does increased exercise affect autophagy?
Increases cell survival and decreases apoptosis
- Decreases levels of misfolded proteins and aggregation
- Ultimate decrease of proteostasis impairment
How many pathways are there for lysosome targeting?
Three
