Lecture 14 - More Membrane Secretion Flashcards

1
Q

What is GspE?

A

An ATPase in type II secretion system

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2
Q

Pilus secretion system similar to T2SS

A

Type 4 pilus

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3
Q

Type 4 pilus system
1)
2)
3)

A

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

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4
Q

Prototypic T3SS

A

Yersinia YOP

pYV-encoded

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5
Q

Yop

A

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

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6
Q

Unusual feature of type 4 pilus secretion

A

Pilus assembly occurs in periplasm

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7
Q

Bacterium that uses type 4 pili

A

Pseudomonas aeruginosa

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8
Q

Use of type 4 pili

A

Twitching motility

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9
Q

Type of bacteria that use T3SS

A

Pathogenic

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10
Q

Effects of Yop insertion on eukaryotic cells

A

Cytotoxicity
Inhibition of phagocytosis
Apoptosis
Inhibition of cytokine release

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11
Q

Yop pore that breaches host cell membrane

A

YopB/D pore

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12
Q

Yop B/D function

A

Membrane pore in host cell

Hydrophobic

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13
Q

Syc

A

Chaperone of proteins translocated in a T3SS

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14
Q

T3SS protein chaperone

A

Syc

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15
Q

Is Yop sec-dependent or independent

A

Independent

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16
Q

Is the N-terminal sequence of Yop proteins cleaved?

17
Q
Generic features of T3SS
1)
2)
3)
4)
5)
A

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

18
Q

Which system has many homologous proteins to T3SS?

A

Flagellum secretion system

T3SS and flagellal basal body look very similar

19
Q

Type IV secretion system background

A

Very similar to bacterial conjugation systems

20
Q

1st protein secreted through a T3SS

A

Hydrophobic host cell membrane channel

21
Q

Which type of proteins can be translocated through T3SS needle?

A

Linear proteins

22
Q

Number of genes required for a T4SS

A

At least 10

23
Q

Best-studied T4SS

A

VirB11, VirB4 of Agrobacterium tumefaciens

24
Q

VirB4, VirB11 function

A

Part of Agrobacterium tumefaciens T4SS

Cytoplasmic ATPases which energise T4SS

25
Cytoplasmic ATPases in Agrobacterium tumefaciens T4SS
VirB4, VirB11
26
Uses of T4SS 1) 2) 3)
1) DNA transfer 2) DNA uptake 3) Virulence 4) Pilus formation (in A tumefaciens, for insertion of virulence proteins)
27
Bacteria which use T4SS 1) 2) 3)
1) Legionella pneumophila 2) Bordatella pertussis 3) Helicobacter pylori
28
What does pertussis use T4SS for?
Secretion of pertussis toxins
29
2 different ways that proteins are trafficked through T4SS
1) With periplasmic stage. EG: pertussis toxin | 2) Without periplasmic stage. EG: DNA, CagA
30
How is pertussis toxin secreted 1) 2) 3)
1) Assembled as a preprotein with a typical signal peptide 2) Transferred through Sec 3) In periplasmic space enters T4SS, secreted
31
T6SS
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
32
Prototypical T6SS
Pseudomonas aeruginosa
33
Which secretion system shares similarities with bacteriophage membrane-puncturing proteins?
T6SS
34
T7SS
1) Newly discovered, not well understood 2) Transports proteins across mycobacterial cell wall 3) In G+ bacteria
35
Name for mycobacterial T7SS
ESX-1 system
36
In a TB infection, antibodies are produced against which part of T7SS?
CFP10, ESAT6