19. V. cholerae

Question 1

Why is the V.cholerae Type IV pilus called the “toxin-coregulated pilus” (TCP)?

Answer 1

Virulence of V.cholerae under coordinated regulation

Environmental signals affect ToxR/ToxS & TcpP/TcpH which activate transcription of ToxT

ToxT activates transcription of tcp promoter

Question 2

Type IV pilus assembly apparatus can also act as what?

Answer 2

Type II secretion apparatus

Question 3

3 key roles of toxin coregulated pili (TCP) in pathogenesis?

Answer 3

1. Microcolony formation
2. TCP assembly secretes TcpF
3. High affinity receptor for the CTX phage

Question 4

Major pilin protein for V.cholerae TCP?

Answer 4

TcpA

Question 5

First step in T4pilin assembly?

Answer 5

Pilin subunits made in cytosol translocated across IM via Sec and inserted into IM

Question 6

3 main V.cholerae virulence factors?

Answer 6

Toxin coregulated pilus (TCP)

Cholera toxin (CT)

TcpF (secreted by TCP apparatus)