Different cell lines different protein stability

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Different cell lines different protein stability

Post by nota82 » Thu Mar 08, 2012 9:20 pm

Hello guys,

I have a quite puzzling and difficult to understand observation.


A) 2 cell lines: A549 (wtp53) and H1299(p53-/-)
B) 2 viruses/proteins: wt and mutant DP
C) A549 Co-IP revealed DP binds cellular FX with remaining 30%
D) H1299 Co-IP revealed DP binds cellular FX with 0%
E) FX stabilizes wt
F) wt binds p53, but p53 is considered to be a negative factor and DP binds p53 inefficiently
G) FX binds p53

following observation:

infection of A549 cells with wt and DP results in no differences of protein expression between wt and DP (WB test) but virus yield is ca. 70% reduced in DP compared to wt. --> DNA replication identical --> other protein levels the same, hence no mRNA change --> proper expression of structural proteins. Thus explaining the virus yield drop is quite difficult.

infection of H1299 cells with wt and DP results in differences in protein expression: less DP, structural proteins, less viral DNA and ca. 90% reduced virus yield. Thus explaining virus yield drop is fairly easy. However, considering A549 results I cannot take these phenotypes into consideration for explaining the negative outcome.

I just want to discuss this issue with somebody. I know there are myriads of explanations, but maybe I am too fuzzy right now to find a good one. Bringing it down to some questions:

1. Does somebody know of a similiar observation? (Article linke preffered, I just need an example for my discussion)

2. A dominant negative effect of DP is possible. Does anyone know an example?

3. Is it plausible that 30% remaining binding of DP to FX can compensate for multiple stability defects which occured in H1299 but not in A549 cells?

4. Is it plausible to discuss that in A549 cells trans-stabilization of FX through p53 on DP occurs?

I would be very happy for some input and a fruitful discussion. There are probably some ambiguities, for this I apologize in advance


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