autophagy 1

Question 1

what is autophagy

Answer 1

self eating
intracellular material is degraded within the lysosome/ vacuole and macromolecular constituents are recycled
stress response pathway

Question 2

sources of membrane for autophagosome formation

Answer 2

er, pm, mitochondria and golgi A

Question 3

er derived autophagosomes

Answer 3

er assiciates with early ap structures
atg48 mutant - unclosed aps attached to er
er is present on inside and outside of forming ap

Question 4

mitochondrial origin of ap

Answer 4

form the outer mitochondrial membrane
requires direct mitochon to er contact
facilitates transfer of phosphatidyl serine that is converted to phosphatidyl ethanolamine (PE)
pe is an essnetial ap lipid component

Question 5

3 kinase complexes that regulate ap formation

Answer 5

mtorc1, ulk1, pi3k

Question 6

mtorc1

Answer 6

inhibits ulk1 in presence of aa’s and gf’s
after aa and gf removal, mtorc1 dissociates from ulk1
ulk1 becomes active and phosphorylates atg13, atg101 and fip200
high levels of glucose inhibits ampk
increase in amp/atp ratio activates ampk
ampk phosphorylates mtorc1 and phosphorylates ulk1

Question 7

building an autophagosome

Answer 7

ub like conjugation drives ap expansion
ub like modifiers are at the heart of ap formation
pi3p helps ap grow

Question 8

ub like modifiers

Answer 8

atg8/lc3/gabarap and atg 12 and atg5 have ub like folds
e1/e2/e3 ub conjugation drives ap expansion
atg12-atg5-atg16 complex acts as e3 to conjugate atg8/lc3 onto autophagosomal membrane
atg8/lc3 proteins are attached to lipids not lysine residues unlike Ub

Question 9

how is the correct cargo seleceted to be degraded

Answer 9

interactions between autophagy receptors and ub like proteins form molecular basis for selective autophagy