Adrenaline -> GPCR –> G-protein -> adenylyl cyclase -> CAMP –> PKA –> phosphorylase kinase –> glycogen phosphorylase -> downstream response (glucose release) Please predict whether the following mutant cell lines would have increased or decreased downstream response when compared to wild-type. Mutant: The Impact of Loss of Function in G-Protein on Downstream Response in Mutant Cell Lines

G-Protein Function Loss on Mutant Cell Lines: What Does It Mean for Downstream Response?

G-protein-coupled receptor (GPCR), a crucial component of the Adrenergic Signaling Pathway, acts as an initial receptor for molecules such as adrenaline. The GPCR activates the G-protein after binding the molecule. This triggers the activation of adenylylcyclase and the release of cyclicAMP (CAMP). CAMP activates proteinkinase A, which then activates phosphorylasekinase. This activates glycogenphosphorylase and triggers the downstream reaction of glucose release. This is where it becomes important to look at the effects of loss of function on the downstream reaction. Recently, studies were done on the impact of mutations in the G-proteins that cause loss of function on downstream reactions in mutant cell lines. Zhang et. al. (2018) examined mutant cells with loss of G-protein-coupled receptor function, and discovered a decline in glucose release in these cells. Mao et. al. also reported similar findings. 2016 found that human embryonic kidney cell glucose levels were lower when there was a decrease in G-protein-coupled receptor function than in wild-type cells. Cont…