Lecture 14 - More Membrane Secretion

Question 1

What is GspE?

Answer 1

An ATPase in type II secretion system

Question 2

Pilus secretion system similar to T2SS

Answer 2

Type 4 pilus

Question 3

Type 4 pilus system
1)
2)
3)

Answer 3

Very similar to T2SS

1) PilA (pre-pilin) made with unusual signal peptide –> not recognised by Sec
2) Signal peptidase on CYTOPLASMIC side of membrane cleaves off signal sequence (PilD)
3) PilA secreted through complex very similar to T2SS

Question 4

Prototypic T3SS

Answer 4

Yersinia YOP

pYV-encoded

Question 5

Yop

Answer 5

In Yersinia
Contact-dependent T3SS
Normally switched off. Switched on when in contact with another cell.
Inserts proteins into cells that disrupt eukaryotic cell function

Question 6

Unusual feature of type 4 pilus secretion

Answer 6

Pilus assembly occurs in periplasm

Question 7

Bacterium that uses type 4 pili

Answer 7

Pseudomonas aeruginosa

Question 8

Use of type 4 pili

Answer 8

Twitching motility

Question 9

Type of bacteria that use T3SS

Answer 9

Pathogenic

Question 10

Effects of Yop insertion on eukaryotic cells

Answer 10

Cytotoxicity
Inhibition of phagocytosis
Apoptosis
Inhibition of cytokine release

Question 11

Yop pore that breaches host cell membrane

Answer 11

YopB/D pore

Question 12

Yop B/D function

Answer 12

Membrane pore in host cell

Hydrophobic

Question 13

Syc

Answer 13

Chaperone of proteins translocated in a T3SS

Question 14

T3SS protein chaperone

Answer 14

Syc

Question 15

Is Yop sec-dependent or independent

Answer 15

Independent

Question 16

Is the N-terminal sequence of Yop proteins cleaved?

Answer 16

No

Question 17

Generic features of T3SS
1)
2)
3)
4)
5)

Answer 17

1) Needle structure that inserts proteins into target cell
2) Contact-dependent function
3) Sec-independent
4) No periplasmic stage
5) Only in pathogenic bacteria

Question 18

Which system has many homologous proteins to T3SS?

Answer 18

Flagellum secretion system

T3SS and flagellal basal body look very similar

Question 19

Type IV secretion system background

Answer 19

Very similar to bacterial conjugation systems

Question 20

1st protein secreted through a T3SS

Answer 20

Hydrophobic host cell membrane channel

Question 21

Which type of proteins can be translocated through T3SS needle?

Answer 21

Linear proteins

Question 22

Number of genes required for a T4SS

Answer 22

At least 10

Question 23

Best-studied T4SS

Answer 23

VirB11, VirB4 of Agrobacterium tumefaciens

Question 24

VirB4, VirB11 function

Answer 24

Part of Agrobacterium tumefaciens T4SS

Cytoplasmic ATPases which energise T4SS

Question 25

Cytoplasmic ATPases in Agrobacterium tumefaciens T4SS

Answer 25

VirB4, VirB11

Question 26

Uses of T4SS
1)
2)
3)

Answer 26

1) DNA transfer
2) DNA uptake
3) Virulence
4) Pilus formation (in A tumefaciens, for insertion of virulence proteins)

Question 27

Bacteria which use T4SS
1)
2)
3)

Answer 27

1) Legionella pneumophila
2) Bordatella pertussis
3) Helicobacter pylori

Question 28

What does pertussis use T4SS for?

Answer 28

Secretion of pertussis toxins

Question 29

2 different ways that proteins are trafficked through T4SS

Answer 29

1) With periplasmic stage. EG: pertussis toxin

2) Without periplasmic stage. EG: DNA, CagA

Question 30

How is pertussis toxin secreted
1)
2)
3)

Answer 30

1) Assembled as a preprotein with a typical signal peptide
2) Transferred through Sec
3) In periplasmic space enters T4SS, secreted

Question 31

T6SS

Answer 31

1) Not very well understood
2) Translocates proteins across bacterial envelope
3) Can insert proteins into target cell using system similar to bacteriophage cell-membrane puncturing protein

Question 32

Prototypical T6SS

Answer 32

Pseudomonas aeruginosa

Question 33

Which secretion system shares similarities with bacteriophage membrane-puncturing proteins?

Answer 33

T6SS

Question 34

T7SS

Answer 34

1) Newly discovered, not well understood
2) Transports proteins across mycobacterial cell wall
3) In G+ bacteria

Question 35

Name for mycobacterial T7SS

Answer 35

ESX-1 system

Question 36

In a TB infection, antibodies are produced against which part of T7SS?

Answer 36

CFP10, ESAT6