Terminating a G protein Coupled Response

The video tutorial explores bio signaling pathways, focusing on how hormone-receptor interactions activate G proteins and lead to cellular responses. It discusses various methods to terminate these responses, including hormone dissociation, phosphodiesterase activity, phosphatase action, and intrinsic GTPase activity. Additionally, the concept of desensitization is explained, highlighting how beta arrestin receptor kinase modulates receptor activity and reduces response magnitude over time.

What is the primary role of epinephrine in bio signaling pathways?

• To bind to adrenergic receptors and activate G proteins

• To inhibit G protein activity

• To phosphorylate proteins directly

• To degrade cyclic AMP

Which enzyme is responsible for the conversion of ATP to cyclic AMP?

• GTPase

• Adenylate cyclase

• Phosphodiesterase

• Protein kinase A

How does phosphodiesterase contribute to the termination of a signaling response?

• By phosphorylating proteins

• By activating G proteins

• By binding to adrenergic receptors

• By converting cyclic AMP to AMP

What is the function of phosphatases in bio signaling pathways?

• To bind to G proteins

• To convert ATP to cyclic AMP

• To remove phosphates from proteins

• To add phosphates to proteins

What happens to the alpha subunit of a G protein when GTP is hydrolyzed to GDP?

• It activates protein kinase A

• It binds to phosphodiesterase

• It dissociates and returns to the regulatory subunit

• It remains active and bound to adenylate cyclase

What intrinsic activity does the alpha subunit of a G protein possess?

• Protein synthesis

• Phosphorylation

• GTPase activity

• Adenylate cyclase activation

What is the role of beta arrestin receptor kinase in desensitization?

• To bind to adenylate cyclase

• To activate G proteins

• To phosphorylate adrenergic receptors

• To degrade cyclic AMP

How does beta arrestin affect the interaction between G proteins and receptors?

• It enhances the binding of GTP

• It stabilizes the interaction

• It destabilizes the interaction

• It converts GDP to GTP

What effect does the invagination of the cell membrane have on adrenergic receptors?

• Decreases the number of receptors on the surface

• Activates all receptors

• Increases the number of receptors on the surface

• Deactivates all receptors

What is the overall effect of desensitization on hormone response?

• Has no effect on hormone response

• Completely blocks hormone response

• Decreases the response to hormones

• Increases the response to hormones