G Proteins 2 Termination of Response

The video explores the mechanisms for terminating the activity of the G protein system. It covers four main methods: using phosphodiesterase to hydrolyze cyclic AMP, employing phosphatases to deactivate enzymes, utilizing nucleotide exchange factors to convert GTP to GDP, and the role of beta arrestin in receptor desensitization. Each method is explained in detail, highlighting the biochemical processes involved and their impact on cellular responses.

What is the primary role of phosphodiesterase in the termination of the G protein system?

• To bind to regulatory proteins

• To phosphorylate proteins

• To hydrolyze cyclic AMP

• To activate cyclic AMP

How do phosphatases contribute to the termination of the G protein system?

• By adding phosphates to enzymes

• By removing phosphates from enzymes

• By converting GTP to GDP

• By binding to cyclic AMP

What is the function of nucleotide translocation factors in the G protein system?

• To interconvert GTP and GDP

• To phosphorylate the alpha subunit

• To bind to beta arrestin

• To convert cyclic AMP to AMP

What happens to the alpha subunit when GTP is replaced by GDP?

• It binds to cyclic AMP

• It phosphorylates proteins

• It becomes active

• It becomes inactive

What role does beta adrenergic receptor kinase play in the termination process?

• It removes phosphates from enzymes

• It phosphorylates the adrenergic receptor

• It converts GTP to GDP

• It hydrolyzes cyclic AMP

How does beta arrestin contribute to the desensitization of the adrenergic receptor?

• By binding to cyclic AMP

• By converting GTP to GDP

• By phosphorylating the receptor

• By causing the G protein to dissociate

What is the result of the G protein dissociating from the adrenergic receptor?

• Phosphorylation of the receptor

• Activation of protein kinase A

• Termination of the adrenergic response

• Increased cyclic AMP production

What is the process called when the receptor becomes less responsive to epinephrine?

• Hydrolysis

• Phosphorylation

• Desensitization

• Activation

Which of the following is NOT a method of terminating the G protein response?

• Phosphatase activity

• Protein synthesis

• Phosphodiesterase activity

• Nucleotide translocation

What happens to adrenergic receptors during desensitization?

• They are degraded

• They increase cyclic AMP production

• They are internalized into vesicles

• They bind more strongly to epinephrine