BCH3021 Lecture Notes - Lecture 22: Neurodegeneration, Antigen Presentation, Peroxisome
Lecture 22 – Core Mechanism: Autophagy I
• Autophagy:
o ‘Self eating’ process – conserved across all eukaryotes that involves
dynamic reorganisation of membranes, and delivery of cellular
material to lysosome for degradation and recycling under times of
nutrient stress
Energy Coupling – Mechanism
• Catabolism
o Rely on reserves: carbohydrates, fats, proteins
• Anabolism
o Uses energy to build
Role of Autophagy
• Nutrient stress
• Maintenance (homeostasis)
o Accumulation of cellular components
o Organelles
▪ If peroxisomes become damaged have to be removed from cell
• Cellular remodelling
o Development
• Pathophysiological conditions
o Tumour suppression
o Intracellular pathogens
o Neurodegeneration
o Antigen presentation
Autophagy is a key Process Conserved in Eukaryotic Cells
Three Types of Autophagy
1. Macroautophagy
2. Microautophagy (originally identified in yeast)
• Only occurs in yeast cells
• Material interacts directly with lysosome
3. Chaperone-mediated autophagy (CMA)
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Document Summary
Lecture 22 core mechanism: autophagy i: autophagy, self eating" process conserved across all eukaryotes that involves dynamic reorganisation of membranes, and delivery of cellular material to lysosome for degradation and recycling under times of nutrient stress. Energy coupling mechanism: catabolism, rely on reserves: carbohydrates, fats, proteins, anabolism, uses energy to build. Role of autophagy: nutrient stress, maintenance (homeostasis, accumulation of cellular components, organelles. If peroxisomes become damaged have to be removed from cell: cellular remodelling, development, pathophysiological conditions, tumour suppression, intracellular pathogens, neurodegeneration, antigen presentation. Autophagy is a key process conserved in eukaryotic cells. Three types of autophagy: macroautophagy, microautophagy (originally identified in yeast, only occurs in yeast cells, material interacts directly with lysosome, chaperone-mediated autophagy (cma) Involves complex of proteins that identify/bind to single substrate proteins complexes interact with liposomal membrane. Autophagic bodies in yeast: degradation of autophagic bodies can be inhibited by treating cells with protease inhibitors inhibiting all proteases in vacuole.
