Lecture 12- Extracellular Vesicles II: Biogenesis, Transport and Function

Question 1

examples of different intraluminal vesicle pathways

Answer 1

ESCRT-dependent pathway
ALIX pathway
TET pathway
ceramide pathway

Question 2

important proteins in ESCRT pathway

Answer 2

ESCRT0-3 complexes
Vsp4, 24, 2

Question 3

role of each ESCRT

Answer 3

0- binds to ubiquitinated proteins
1- clusters ubiquitinated proteins
2- engages cargo
3- helps define the ring structure

Question 4

mechanism of ALIX pathway

Answer 4

syndecan in membrane binding with sintenin, pulls membrane to form early vesicle, then ESCRT3-Vsp4 pulls it closed

Question 5

TET features

Answer 5

abundant in many membranes, 4 membrane spanning a helix domains

Question 6

how does sphingomyelin form

Answer 6

sphingomyelin hydrolysed by nSMase2

Question 7

how are microvesicles formed

Answer 7

recruitment of actin and cytoskeletal proteins
ceramides involved, but lipids are flipped, leading to outward budding

Question 8

what are MVBs and how are they transported

Answer 8

multivesicular bodies- part of the endosomes which sort membrane proteins into the correct vesicles
transport via microtubule motors powered by GTPases

Question 9

processes in which vesicles are important

Answer 9

fertilisation, implantation, sperm motility, pathogenesis

Question 10

how are vesicles important in sperm motility

Answer 10

prostasomes- these allow transport of ADPR cyclase into sperm, which increases Ca2+ conc, helping increase sperm motility- removing EVs can block motility

Question 11

role of vesicles in covid infection

Answer 11

platelet tissue factor in covid-infected EVs, causing excessive blood clotting- associated w poor prognosis