GPCR Signal Transduction Interactive

Extracellular fluid

Cytoplasm

Ligand

G protein-coupled receptor

G protein

GDP

GTP

Adenylyl
cyclase

Inactive protein kinase A

Inactive target protein P

ATP

Order the Steps

Match each event to its place in the GPCR signaling sequence.

Answer Questions

Answer the questions below. When you are finished, use the print button to save your responses.

Name

1. At what specific point in the process does the signal move from outside the cell to inside the cell?

2. How does PKA activate its target protein?

3. How does the G protein become inactivated?

4. This model shows a 1:1 relationship between binding events and enzymatic events, which is a simplification. For example, only one ATP was converted into cAMP when the G-protein was bound to it. As a result, signal amplification is not shown in this model. Explain how the model could be changed to show signal amplification.