Lecture 3 - Influenza and PHA Flashcards
Influenza virion contains…
genetic sequences for glycoproteins
Haemagglutinin
binds to silica acid residues to activate PKC and transient inhibition of ENaC
M2
forms an acid-activated, amantadine-inhibited H+ channel, inserted into the apical membrane host cell
M2 is involved in…
long term ENaC regulation
M2 overexpression
reduction in channel number. Control shows two channels opening but this shows only one
ENaC alpha and beta subunits in M2
both reduced in presence therefore reduced channel number
ENaC current at M2 overexpression
reduced
M2 over expression and endocytosis in Liddle’s patient
in mutant endocytosis is reduced but not to the same extent as control, endocytosis is occurring as otherwise currents would disappear
Ros and M2 absence
no to little Ros
Ros and M2 overexpression
lots of Ros and colocalisation of Ros and M2
GSH
antioxidant reversing M2 inhibition which proves M2 overepxression increases Ros levels
G-6796 and inhibitor
different PKC isoform inhibitors, shows inhibition reversal. M2 overexpression shows increased PKC
Why is the literature conflicted about flu?
different papers say increased or decreased ASL.
What could be potential reasons for literature conflict>
cell source
influenza virus properties
lab conditions
or this could actually be what occurs in vivo
what is forskolin used for?
measuring CFTR function
why are there two bands of CFTR?
one band represents immature channels
What is the mature CFTR?
band 3, the only ones that function
Mature CFTR and M2
when over expressed there is reduced mature CFTR in the whole cell and PM
DsiM2
M2 knockdown
Why is DsiScram used?
as a control
infected cells and DsiM2
show inhibition in both control and M2 KD - inhibition exclusively mediated by M2
Infected cells and M2 inhibition
CFTR currents return to normal
Udorn virus M2 aman-sensitive
blocks H+ function
M2 and pH
M2 mediates H+ movement therefore changing the pH and targets CFTR for lysosomal degradation
Bafilomycin
prevents lysosomal acidification
Lactacystin
prevents proteosomal degradation
ENaC gain of function mutations (4)
Liddle’s syndrome
hypertension
increased ENaC
Nedd4 channel retrieval
ENaC loss of function mutations (2)
PHA (Pseudohypoaldosteronism)
ENaC inactivation
Pseudohypoaldosteronism results in…
salt wasting hypotension hyperkalaemia metabolic acidosis high renin and aldosterone
PHA is genetically…
autosomal recessive
PHA affects…
multiple organs
In PHA all ENaC…
subunits are mutated
PHA symptoms
frequent lower RTI, permanent runny nose due to increased nasal liquid and blockages in nasal passages, excessive sodium in nasal discharge consistent with ENaC inhibition
Vte in PHA
reduced
