Question

All following events occur in G-protein-coupled receptor signaling leading to transcription of genes with cAMP response elements. Which one is the last.

A. Activation of CREB by PKA
B. Binding of cAMP to PKA
C. Dissociation of PKA into catalytic and regulatory subunits
D. Activation of adenylyl cyclase

Answer 1

In G-protein-coupled receptor signaling, the last event that occurs before transcription of genes with cAMP response elements is the activation of CREB by PKA, after adenylyl cyclase activation, cAMP binding to PKA, and dissociation of PKA into its subunits.

Step-by-step explanation:

In the process of G-protein-coupled receptor signaling leading to transcription of genes with cAMP response elements, the sequence of events is as follows:

Activation of adenylyl cyclase, which catalyzes the conversion of ATP to cAMP.

Binding of cAMP to the regulatory subunits of Protein Kinase A (PKA).

Dissociation of PKA into catalytic and regulatory subunits, where the catalytic subunits are now active.

Activation of cAMP response element-binding protein (CREB) by PKA through phosphorylation.

The last event in this signaling cascade is the activation of CREB by PKA, which directly links to the transcription of genes containing cAMP response elements.