2. Back in lab, you treat liver cells with a high concentration of a membrane pe
ID: 266704 • Letter: 2
Question
2. Back in lab, you treat liver cells with a high concentration of a membrane permeable cAMP analog (stable molecule, similar to cAMP, that can mimic cAMP in the cell) A. (3pts) You are able to measure two downstream responses to the cAMP analog. Please circle whether these are relatively FAST or SLOW responses. Phosphorylation of PKA Transcript levels of a target gene FAST or SLOWw FAST or SLOW B. (3pts) Explain your above choices and why these make most sense based on your understanding of the timescales of cellular signaling.Explanation / Answer
Please find the answers below:
Answer 2:
Answer A: The cAMP dependent signalling involves enzymatic bioconversion of cAMP in the presence of enzyme PKA. Activation of this enzyme in the presence of cAMP takes place by phosphorylation. Analogues are those chemical species which replace/mimic the biomolecule in the cells and hence replace their function. Analogues do not reduce or down-regulate the original function but only mimic the action of actual biomolecule. Hence, use of cAMP analogue will lead to:
Fast PKA phosphorylation, Fast gene transcription.
Answer B: As soon as either cAMP or its analogue enters the cell, it starts a series of biochemical reactions which involve phosphorylation and activation of PKA. This PKA mediates transcriptional activation of various biomoleucles which rapidly transit into the nucleus leading to enhanced gene expression. All these events take place in fraction of minutes thus, addition of cAMP analogue to the medium will definitely ensure enhanced levels of PKA activation and gene expression.
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