Medical College of Wisconsin
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Calcium-dependent dephosphorylation mediates the hyperosmotic and lysophosphatidic acid-dependent inhibition of natriuretic peptide receptor-B/guanylyl cyclase-B. J Biol Chem 2004 Nov 19;279(47):48513-9 PMID: 15371450


C-type natriuretic peptide binding to natriuretic peptide receptor-B (NPR-B) stimulates cGMP synthesis, which regulates vasorelaxation, cell proliferation, and bone growth. Here, we investigated the mechanistic basis for hyperosmotic and lysophosphatidic acid-dependent inhibition of NPR-B. Whole cell cGMP measurements and guanylyl cyclase assays indicated that acute hyperosmolarity decreased NPR-B activity in a reversible, concentration- and time-dependent manner, whereas chronic exposure had no effect. Acute hyperosmolarity elevated intracellular calcium in a concentration-dependent fashion that paralleled NPR-B desensitization. A calcium chelator, but not a protein kinase C inhibitor, blocked both calcium elevations and desensitization. Hyperosmotic medium stimulated NPR-B dephosphorylation, and the receptor was rapidly rephosphorylated and resensitized when the hypertonic media was removed. Lysophosphatidic acid also inhibited NPR-B in a calcium- and phosphorylation-dependent process, consistent with calcium being a universal regulator of NPR-B. The absolute requirement of dephosphorylation in this process was demonstrated by showing that a receptor with glutamates substituted at all known NPR-B phosphorylation sites is unresponsive to hyperosmotic stimuli. This is the first study to measure the phosphorylation state of an endogenous guanylyl cyclase and to link intracellular calcium elevations with its dephosphorylation.

Author List

Potthast R, Abbey-Hosch SE, Antos LK, Marchant JS, Kuhn M, Potter LR


Jonathan S. Marchant PhD Chair, Professor in the Cell Biology, Neurobiology and Anatomy department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Binding Sites
Cell Line
Cell Proliferation
Cells, Cultured
Cyclic GMP
Dose-Response Relationship, Drug
Guanylate Cyclase
Microscopy, Confocal
NIH 3T3 Cells
Receptors, Atrial Natriuretic Factor
Receptors, Peptide
Sodium Chloride
Time Factors

View this publication's entry at the Pubmed website PMID: 15371450
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