Question

Which of the following steps are required in the activation of the G-protein signaling pathway?

1) Ligand binds to the G-protein-coupled receptor.
2) Gα exchanges GDP for GTP.
3) Activated Gα influences target proteins.
4) The activated receptor induces interaction between Gα and Gβγ.

Answer 1

The steps required in the activation of the G-protein signaling pathway include ligand binding to the G-protein-coupled receptor, Gα exchanging GDP for GTP, activated Gα influencing target proteins, and the activated receptor inducing interaction between Gα and Gβγ.

Step-by-step explanation:

The activation of the G-protein signaling pathway involves several steps:

1. Ligand binds to the G-protein-coupled receptor: Before activation, the receptor is in an inactive state. When a ligand, such as a hormone or neurotransmitter, binds to the receptor, it causes a conformational change in the receptor.
2. Gα exchanges GDP for GTP: The activated receptor induces the exchange of guanosine diphosphate (GDP) bound to the Gα subunit of the G-protein for guanosine triphosphate (GTP).
3. Activated Gα influences target proteins: The Gα subunit with bound GTP can now interact with various target proteins, activating or inhibiting their functions, depending on the specific signaling pathway.
4. The activated receptor induces interaction between Gα and Gβγ: The activated receptor also promotes the interaction between the Gα subunit and the Gβγ subunit of the G-protein.