Save
Busy. Please wait.
or

show password
Forgot Password?

Don't have an account?  Sign up 
or

Username is available taken
show password

why


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.


Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
focusNode
Didn't know it?
click below
 
Knew it?
click below
Don't know
Remaining cards (0)
Know
0:00
share
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

CFTR

QuestionAnswer
Verkman & Galietta 2009 Review: Absence of specific blockers has hampered research. High throughput is producing some channel modulators and inhibitors (generally drugs for other uses). CaCC (TMEM16A) inhibitors were promising but fell through, only recently identified TMEM16A
Barrett & Keely 2000 Review: Nutrient transporters tend to be obligate water conductors. Paracellin is involved in cation selectivity of paracellular transport. Adenosine activates CFTR through cAMP, neutrophils release adenosine precursor in some diseases.
Zhang et al 2010 CFTR activated by small amounts of stretch, 61% of cells responded to stretch. PKA and PKC blockers had no effect, indicating there isnt a 2nd messenger system. Effects still see in Ca free soln. Current also seen in tissue, blockable with CFTR inhibitor
Simon et al 1999 Shows paracellin is important in selectivity of paracellular cation transport. May be a channel. Mutations cause Mg2+ wasting
George et al 2009 Review: treatment. Nebulised antibiotics, mannitol. Biofilms are the danger, grow slowly but can be 1000x more resistant. CF sputum can contain 10+ P.aeru colonies each with different resistance. Benzamil is an ENaC blocker potentiating aminoglycosides
Famesol Quorum sensing molecule w possible use as a trojan horse, may be a particular vulnerability of biofilms.
Clarke & Harline 1996 Shows cAMP regulates chloride secretion as well as absorption of both sodium and chloride. Also found that CFTR was responsible for most if not all effects of cAMP on Na/Cl homeostasis
Egan et al 1992 Possible regulation of outward rectifier Cl channels (ORCC) by CFTR. CFTR reintroduced to rescue defective outward rectification, had these effects in addition to the obvious effects of adding CFTR channels
Boucher et al 1986 CF airways have abnormally high sodium reabsorption. Beta agonists stim cAMP and cause increased Cl secretion in normal airways, in CF they simply increase Na absorption (reducing ASL). Used short cicuit current, isolated Na contribution using amiloride
Stutts et al 1995 Cells expressing ENaC without CFTR showed increased sodium absorption in response to forskolin. By contrast, addition of CFTR prevented this increase, causing a decrease instead. May be due to ATP release through CFTR (similar to ORCC regulation)
Kunzelmann et al 1997 Shows direct protein-protein interaction between CFTR and ENaC. Intracellular CFTR fragment containing NBD1 and R domain was sufficient to restore regulation. Colocalisation may be to increase ATP concn at ENaC or simple direct action through protein link
Fulmer et al 1995 Showed that of two intracellular mutation both allowed Cl conductance but the more severe disease was linked with an inability to regulate ORCC. Same mutation that failed ENaC regulation in Kunzelman 97, role in ATP extrusion or attachment to scaffold?
Schweibert et al 1995 Same group as Fulmer. Trapping of extracellular ATP by hexokinase prevented the CFTR-ORCC interaction. Study also shows conclusively that CFTR causes ATP efflux.
Bradbury 1999 (only author) Review: Discusses a possible role for CFTR in vesicle trafficking, may be that CFTR acts as an intracellular channel protein before reaching the membrane. Important as mucus is excreted by exocytosis.
Lu et al 2006 CFTR interacts with ROMK, mediating response to intracell ATP and glibenclamide. Reqd for glibenclamide block of ROMK, like SUR proteins. Interaction may be via a scaffolidng protein. Glibenclamide strange as it has previously been used to block CFTR
Loussouarn et al 1996 Shows that cells transfected with CFTR gain a cAMP stimulated K+ current which may be ROMK. Used whole cell patch clamping. Interferon also reduces the K+ current in line with CFTR gene reduction.
Mall et al 2004 Transgenic mice with increased Na absorption (by increased ENaC) show reduced survival, due to mucus plugs rather than infection foci. Better mouse model than CFTR dysfunction
Garcia et al 2009 HCO3 secretion is required for mucin secretion, basal levels the same but on PGE/5HT stimulation HCO3 free preps produced less. Adding luminal HCO3 didnt help. No ENaC dependent sodium absorption in the biliary tree (so these symptoms must be CFTR).
Sugita et al 1998 Evidence suggesting ATP is extruded by a closely associated but separate pore which relies on CFTR entirely. Found multiple Cl channels associated with 1 or 2 ATP channels, if same protein numbers would be equal. Channels were pharmacologically distinct.
Poulsen et al 1994 CFTR also conducts HCO3. Forskolin dependent pH change didnt occur in HCO3-free + CO2-free solution. HCO3 permeability 1/4 of Cl-. pH will be lower in CF epithelial lumen. F508 mutants have poor HCO3 conductance.
Caputo et al 2008 Identifies the CaCC channel as TMEM16A. IL4 was known to regulate CaCC so they looked for genes regulated by IL4. siRNA screen of putative targets to disrupt CaCC. Exploited halide sensitivity of YFP to assay I- influx.
Murek et al 2010 Review: Covers intestinal chloride secretion although criticised by Lucas 2010 for taking too much of the in vitro data for granted and relying heavily on short-circuit currents
Gyomorey et al 2000 ClC2 protein appears to be present in intestine, CFTR KO mice show a conductance that exhibits the properties expected for ClC. Uses Ussing chambers and short-circuit currents. Odd distribution, close to tight junctions.
Created by: Jonmassie
 

 



Voices

Use these flashcards to help memorize information. Look at the large card and try to recall what is on the other side. Then click the card to flip it. If you knew the answer, click the green Know box. Otherwise, click the red Don't know box.

When you've placed seven or more cards in the Don't know box, click "retry" to try those cards again.

If you've accidentally put the card in the wrong box, just click on the card to take it out of the box.

You can also use your keyboard to move the cards as follows:

If you are logged in to your account, this website will remember which cards you know and don't know so that they are in the same box the next time you log in.

When you need a break, try one of the other activities listed below the flashcards like Matching, Snowman, or Hungry Bug. Although it may feel like you're playing a game, your brain is still making more connections with the information to help you out.

To see how well you know the information, try the Quiz or Test activity.

Pass complete!

"Know" box contains:
Time elapsed:
Retries:
restart all cards