Lecture 4 Extra Reading

Question 1

What detergents are used and what are DRMs?

Answer 1

cold, non-ionic detergents, detergent resistant membranes

Question 2

Explain how GPR-APs can be sorted to apical or basolateral membrane in an anchor dependent or independent manner

Answer 2

Sphingoplipids and cholesterol may form odered domains in the golgi and recruit GRP-APs. they are sorted into vesicles for targeting to the apical membrane in polarised epithelial cells. N-glycosylation of the protein, but not its GPI anchor is responsible for apical targeting. DRM association doesn’t necessarily correlate with apical sorting as it depends on oligomerisation. GPIs with unsaturated fatty acids are delivered to the PM just as easily.

Question 3

Describe another explanation for phenomena attributed to rafts

Answer 3

favourable interactions between hydrophobic/hydrophilic proteins and lipids could lead to the formation of protein complexes of up to 100 lipids.

Question 4

What distance does movement of a protein affect other proteins?

Answer 4

3-4 nm

Question 5

What is Laurdan? What does its half life mean?

Answer 5

A membrane dye. Decreased fluorescence lifetime in less hydrated environments

Question 6

What could a decreased Lauran fluorescence life time mean in terms of rafts and not with rafts?

Answer 6

less hydrated environment occurs in liquid ordered phase or due to annular lipids with more mobility.