Sources of Superoxide

Question 1

How does p47 interact with p67?

Answer 1

In inactive state p47 C-terminal proline-rich SH3 domain interacts with own SH3 domain to prevent CytB binding.
Activated –> C terminal Pro-rich domain occupied by C terminal SH3 domain of p67.

Question 2

Briefly outline phagocytosis

Answer 2

Membrane pseudopodia
Bacteria ingested --> phagosome forms.
Lysosomes and phagosomes fuse, enzymes released
Digestion of material (ox burst) 
Product release.

Question 3

Where do antimycin and stigmatellin act?

Answer 3

ST - inhibits transfer of electrons from QH2 to Fe2S2.
Antimycin blocks transfer of second election from CytB to RELATIVELY STABLE semiquinone at Qi site –> unstable semiquinone at Qo site accumulates.

Question 4

What does NOX3 regulate?

Answer 4

High expression in kidneys.

Controls renal oxygenation, tubuloglomerular feedback and Na+ transport.

Question 5

What is the role and structure of NOX1?

Answer 5

Serotonin biosynthesis, motility and secretion. High expression in colon epithelium.
NOXO1 = p47 homologue
NOXA1 = p67 homologue
Needs p22, Rac and cytosolic subunits for activation.