Organelle Ecology - the ER and self organisation

Question 1

how can endomembrane lipids change

Answer 1

stresses within the membrane such as temp or movement changes need a response, to maintain stability- lateral diffusion pf lipids, composition changes

Question 2

example of a mechanism which prevents problematic membrane lipid changes

Answer 2

CCTalpha acting as a sensor if the typical lipid composition is deviated from- prevents unfolding etc from occurring

association with ER promoted when there are conical/anionic lipids present

Question 3

importance of membrane structure for protein binding

Answer 3

different amphipathic helices require different membrane structures, and these are very important for targeted localisation of other proteins

Question 4

‘lipid raft’

Answer 4

microdomains within the plasma membrane, generally self-organising (can see through lipid staining experiments)

important for protein partitioning

Question 5

examples of how curvature can be induced

Answer 5

lipid modifications
wedge-shaped proteins
direct protein interactions with lipids
amphiphatic helix insertion- and potential subsequent protein interactions

Question 6

factors involved in making tubes

Answer 6

reticulon proteins
amphiphatic helices
atlastin GTPases- drive tubule fusion
cytoskeletal interactions drive tubule extension

Question 7

example of cisternae structural elements

Answer 7

luminal spacers- e.g. climp63
scaffolding proteins to keep surface flat- e.g. p180
lunapark proteins to stabilise three-way junctions

Question 8

essay- ‘how are endomembrane structures established and maintained?’

Answer 8

lipid rafts and protein attachments- important so right proteins are in the right places etc
membrane curvature in processes like fission and endocytosis
making tubes
making cisternae