Exosomes & Multivesicular Bodies

Question 1

What do vesicles that bud inwards into endosomes give rise to?

Answer 1

Multivesicular endosomes
(Multivesicular bodies)

Question 2

What is the lumen of multivesicular endosomes equivalent to?

Answer 2

Cytosol
(NOT the extracellular space)

Question 3

What are vesicles that bud outwards from the plasma membrane into the extracellular space called?

Answer 3

Extracellular vesicles

Question 4

How many different proteins does the Endosomal Sorting Complexes Required for Transport (ESCRT) consist of?

Answer 4

Four

Question 5

What size are Exosomes generally?

Answer 5

Less than 150nm in diameter

Question 6

What shape are Exosomes generally?

Answer 6

Round

Question 8

What do Exosomes contain?

Answer 8

• Protein
• Nucleic Acids
• Lipids
• Other metabolites

Question 10

What THREE things can happen to Extracellular Vesicles (EVs) after binding to recipient cells?

Answer 10

1. Remain stably associated with the plasma membrane
2. Fuse with the plasma membrane
3. Be internalised by endocytic pathways

Question 11

What are the roles of Extracellular Vesicles (EVs) in the Immune System and Cancer?

Answer 11

• Act as antigen-presenting vesicles
• Stimulate antitumoural immune responses
• Used diagnostically as biomarker in disease
• Promote angiogenesis and tumour cell migration and mestastases

Question 12

What are the roles of Extracellular Vesicles (EVs) in the Brain?

Answer 12

• Participate in myelin formation, neurite outgrowth and neuronal survival
• Can participate in spreading pathogenic proteins to recipient cells

Question 13

What is the Autophagic Pathway?

Answer 13

Delivers cytosolic proteins and organelles to lysosomes for degradation