15 - Autophagy I Flashcards
What is autophagy?
A mechanism to digest intracellular material.
Why do cells need to degrade?
For:
- Homeostasis
- Signalling
- Removing damaged components
- Reprogramming cells
- Recycling nutrients
What are the 2 mechanisms for degradation?
1) The ubiquitin/proteosome system
2) Autophagy - Macro autophagy
- Chaperone-mediated autophagy
- Micro autophagy
Describe the proteosome pathway for degradation
Its non lysosomal, degrades the individual proteins and has a major turnover rate.
Describe the pathway for macro autophagy.
Its a lysosomal, bulk digestion pathway, it can remove whole organelles and the molecules released can support metabolism.
Describe the pathway of chaperone mediated autophagy.
Its also lysosomal but it only degrades individual proteins it also turns over specific long lived proteins.
What is the importance of nutrient recycling aspect of autophagy?
Autophagy is rapidly upregulated under starvation causing non selective bulk degradation of the cytosol recycling the nutrients.
Cells that lack autophagy die under starvation.
How is cellular remodelling a function of autophagy?
Autophagy is the only mechanism to degrade organelles, essential to for some specific cell types.
What is erythropoiesis?
Red blood cell differentiation.
What function of autophagy helps with ageing and neurodegeneration?
Removal of damaged components.
why is removal of damaged components needed to help with ageing and degeneration?
Cellular components accumulate damage overtime. and lysosomal capacity decreases as we age so autophagy is needed to get rid of the old and damaged cells.
What is the dietary restriction hypothesis?
Putting your body under starvation/exercise increases autophagy which in turn increases the body’s damage repair.
Why is autophagy needed to kill intracellular pathogens?
Because some pathogens beat the immune responses and escape into the cytoplasm.
How does nutrient recycling help to fight disease?
It helps with surviving starvation.
What is a disadvantage of nutrient recycling in disease?
It may prolong cancer or cause tumours to last longer than they should.
