Organelle Ecology- the Golgi

Question 1

opposing theories of how the Golgi works

Answer 1

compartmental maturation- stuff stays in the same compartment, you add and remove the things doing the processing
vesicle trafficking- moving between compartments in order

Question 2

name of the ER Golgi intermediate compartment

Answer 2

Ergic- er golgi intermediate compartment

Question 3

evidence of maturation

Answer 3

live cell imaging- imaging formation of the VTC, as well as changes in protein coat representing identity change (different fluorescent stains)

tracking calcium carbonate scales through coccolith cells- don’t fit in vesicles so it’s clearly not that
> see same thing in collagen

biochemical evidence of enzymatic changes, and cargo similarity, along the Golgi stack

direct observation of transport- VSVG assays

Question 4

numbers of golgi components

Answer 4

very variable- could have 3, could have up to 20, depending on the organism- evolutionary flexibility

Question 5

cisternal maturation model- extension

Answer 5

small cargoes can move between golgi stacks through tubular connections- can see this using gold tracing experiments

Question 6

lipid ratchet

Answer 6

idea that cisternae are continuously self-sorting, no trans/cis etc

Question 7

driver of changes in organelle identity- what is it, and why is the mechanism sensible?

Answer 7

Rab-GTPase cascades- recruiting each other, automatic so you get progression - but hard to prove

plasticity- short-lived molecules, so composition can easily be changed and lead to rapid switching when it is appropriaye

Question 8

fundamentally- how does the Golgi organise itself?

Answer 8

self-organisation through lipid modification (Rab GTPases)