Which statement about GPCRs is true?

Which statement about GPCRs is true?

• A. Most abundant class of receptors in the human body
• B. They are direct ion channels
• C. They have 2 transmembrane helices
• D. They function only in the nervous system

Answer: (A)

GPCRs are the largest and most diverse family of cell-surface receptors in humans, activated when a ligand binds to the receptor’s seven transmembrane helices and triggers coupling to heterotrimeric G proteins. This signaling setup allows a single receptor family to respond to a wide range of signals—hormones, neurotransmitters, and various sensory inputs—and to influence many tissues, not just the nervous system. They are not direct ion channels; instead, they convey signals indirectly by regulating enzymes and ion channels through G proteins. The seven-transmembrane architecture, broad distribution, and widespread functional roles all explain why this class is considered the most abundant receptor type in the human body.

GPCRs are the largest and most diverse family of cell-surface receptors in humans, activated when a ligand binds to the receptor’s seven transmembrane helices and triggers coupling to heterotrimeric G proteins. This signaling setup allows a single receptor family to respond to a wide range of signals—hormones, neurotransmitters, and various sensory inputs—and to influence many tissues, not just the nervous system. They are not direct ion channels; instead, they convey signals indirectly by regulating enzymes and ion channels through G proteins. The seven-transmembrane architecture, broad distribution, and widespread functional roles all explain why this class is considered the most abundant receptor type in the human body.