Question

Indicate by writing "yes" or "no" whether amplification of a signal could occur at the particular steps described below. Explain your answers.

A. An extracellular signaling molecule binds and activates a GPCR.
B. The activated GPCRs cause Gα to separate from Gβ and Gγ.
C. Adenylyl cyclase produces cyclic AMP.
D. cAMP activates protein kinase A.
E. Protein kinase A phosphorylates target proteins.

Answer 1

Amplification of a signal could occur at various steps in the G-protein signaling pathway, including the binding of an extracellular signaling molecule to activate a GPCR, GPCR activation of Gα to separate from Gβ and Gγ, production of cAMP by adenylyl cyclase, activation of protein kinase A by cAMP, and phosphorylation of target proteins by protein kinase A.

Step-by-step explanation:

Yes, amplification of a signal could occur at the particular steps described below:

1. An extracellular signaling molecule binds and activates a GPCR: This activation leads to the activation of multiple Gα subunits, amplifying the signal.
2. Activated GPCRs cause Gα to separate from Gβ and Gγ: This separation allows for the activation of multiple adenylyl cyclase enzymes, leading to the production of multiple cyclic AMP (cAMP) molecules, which amplifies the signal.
3. cAMP activates protein kinase A: This activation can lead to the activation of multiple protein kinase A molecules, which in turn can phosphorylate multiple target proteins, further amplifying the signal.
4. Protein kinase A phosphorylates target proteins: This phosphorylation can lead to the activation of multiple target proteins, resulting in the amplification of the signal.