Atrial natriuretic peptide (ANP) binds to its receptor on vascular smooth muscle, promoting vasodilation and natriuresis. Which of the following best describes the ANP receptor mechanism?

• A It is a G protein-coupled receptor that activates adenenylyl cyclase via Gs
• B It is a receptor tyrosine kinase that autophosphorylates on ligand binding
• C It is a transmembrane receptor with intrinsic guanylyl cyclase activity that produces cGMP ✓
• D It is a nuclear receptor that binds to DNA response elements and regulates gene transcription

Explanation

The type A natriuretic peptide receptor (NPRA) is a single-pass transmembrane protein with an intracellular guanylyl cyclase domain. Ligand binding activates this domain, increasing intracellular cGMP, which activates PKG and causes smooth muscle relaxation. GPCRs use G proteins, receptor tyrosine kinases autophosphorylate tyrosine residues, and nuclear receptors regulate transcription. None of these describe ANP signaling.

Reference: Harper's Illustrated Biochemistry, 31st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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