Lecture 11 - Bacterial Cell-Cell spread Flashcards
Advantages to intracellular pathogenesis 1) 2) 3) 4) 5)
1) Privileged environment (no competition)
2) Inaccessible to attack by complement, antibodies
3) No need to adhere to host cell
4) Readily available nutrients
5) Necessary, if obligate intracellular pathogen
What is a chemoheterotroph?
Organisms that use carbon sources as energy.
EG: Compounds from host cell interior
Intracellular niches
1)
2)
3)
1) Intralysosomal (low pH, hydrolytic)
2) Intravacuolar (neutral pH)
3) Cytosolic
Professional phagocytic cells
Macrophages, neutrophils, dendritic cells (kind of)
Which niche does Listeria live in?
Intracellular, cytosolic
How does Shigella escape vacuoles?
Phospholipases digest vacuole membrane
How does Shigella cause macrophages to undergo apoptosis?
Stimulate inflammosomes
Causes pro-caspase 1 activation, IL-1b, IL-18 release, pyroptosis
Shigella protein used for actin recruitment
IcsA
Which bacteria is IcsA found in?
Shigella
Protein type of IcsA
Autotransporter
IcsA function
1)
2)
3)
1) Binds N-WASP to glysine-rich region
2) N-WASP has two binding grooves, one for monomeric actin, one for Arp2/3 complex
3) Arp2/3 complex nucleates actin, actin chain begins formation
N-WASP interaction domains 1) 2) 3) 4)
1) CDC42
2) Nck
3) Actin
4) Arp2/3
Which part of IcsA binds N-WASP?
Glycine-rich region
What does the glycine-rich region of IcsA do?
Recruit N-WASP
N-WASP function
1)
2)
1) Has binding site for monomeric actin, Arp2/3
2) Supplies monomeric actin to Arp2/3