IST3G- The epinephrine signaling pathway plays a role in regulating glucose homeostasis in muscle cells. The signaling pathway is activated by the binding of epinephrine to the beta-2 adrenergic receptor. A simplified model of the epinephrine signaling pathway is represented in Figure 1.

Which of the following outcomes will most likely result from the irreversible binding of GDP

to the G protein?

Question

IST3G- The epinephrine signaling pathway plays a role in regulating glucose homeostasis in muscle cells. The signaling pathway is activated by the binding of epinephrine to the beta-2 adrenergic receptor. A simplified model of the epinephrine signaling pathway is represented in Figure 1.

Which of the following outcomes will most likely result from the irreversible binding of GDP

to the G protein?

BlackTom AI · Accepted Answer

In this question, we’re examining the consequence of irreversible GDP binding to the G protein within the epinephrine signaling pathway that involves the beta-2 adrenergic receptor and its Gs protein.

First, consider what GDP-bound G protein implies: the G protein is in an inactive state and cannot exchange GDP for GTP to become ACTIVE. Without active Gs, the receptor cannot stimulate adenylate cyclase, so cAMP production would drop and downstream PKA signaling would be reduced.

If GPCR signaling is blunted, the cascade that promotes glycogen breakdown (glycogenolysis) via phosphorylation events is diminished. In muscle (and liver) cells, epinephrine normally promotes glycogen breakdown to release glucose; this process is driven by Gs activation leading to increased cAMP and activation of glycogen phosphorylase. Therefore, blocking Gs activation would tilt the balance away from glycogenolysis.

As a result, the intracellular glycogen stores would be expected to increase or at least not be mobilized efficiently, since the signal to degrade glycogen is not transmitted.

Note on the provided options: the only listed option states that 'The intracellular concentration of glycogen will increase.' This aligns with the mechanistic expectation that irreversible GDP binding prevents GPCR-mediated glycogenolysis. If there were other options, they might include outcomes like decreased glycogen breakdown, reduced cAMP levels, or unchanged glycogen levels; however, none are presented here.

Thus, the reasoning supports the conclusion that irreversible GDP binding to the G protein would lead to an accumulation or preservation of glycogen in the cell due to inhibited epinephrine-induced glycogenolysis.

类似问题

Why are membrane receptors required for insulin signalling?

Which statement explains how the same second-messenger molecule, cAMP, can be involved in different pathways in different cells?

An agonist is a ligand that binds to, and provokes a signal from a receptor via conformational changes in the excited state.

A protein such as epidermal growth factor (EGF) is MOST LIKELY to:

Which of the following is NOT an example of a receptor tyrosine kinase?[Fill in the blank]

Question at position 44 A hormone is an example of which type of cell cycle signal?endogenousexogenous

G protein receptor is a

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单