RGD Reference Report - Forced homodimerization by site-directed mutagenesis alters guanylyl cyclase activity of natriuretic peptide receptor B. - Rat Genome Database

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Forced homodimerization by site-directed mutagenesis alters guanylyl cyclase activity of natriuretic peptide receptor B.

Authors: Langenickel, T  Buttgereit, J  Pagel, I  Dietz, R  Willenbrock, R  Bader, M 
Citation: Langenickel T, etal., Hypertension. 2004 Feb;43(2):460-5. Epub 2003 Dec 22.
RGD ID: 1601491
Pubmed: PMID:14691198   (View Abstract at PubMed)
DOI: DOI:10.1161/01.HYP.0000110907.33263.0b   (Journal Full-text)

Natriuretic peptides mediate their physiologic effects through activation of membrane-bound, guanylyl cyclase-coupled receptors (NPRs). Receptor dimerization is an important feature of signal transduction. This study was aimed at characterizing structurally important residues of the extracellular ligand-binding domain of NPR-B for receptor dimerization and cGMP generation. Deletion mutagenesis was used to replace cysteine residues at positions 53 (C53S), 417 (C417S), and 426 (C426S) by serine. Receptor expression, dimerization, whole-cell cGMP response, and guanylyl cyclase activity of membrane fractions were determined in stably transfected COS-7 cells. C53S, C417S, and C426S mutants were expressed and found to form disulfide-bridged covalent dimers. In contrast to NPR-B and C53S, C417S and C426S mutants displayed constitutive activity in whole cells (C417S, 146+/-12%, P<0.01; C426S, 153+/-7% of ligand-independent NPR-B cGMP generation, P<0.01). The cGMP response of C417S and C426S mutants in whole cells was dose dependent and approximately 4 times lower than that in NPR-B, whereas it was blunted in C53S-transfected cells (1 micromol/L CNP, NPR-B 2868+/-436%; C53S, 206+/-16% of control, P<0.001 vs NPR-B, C417S, and C426S). Guanylyl cyclase assay in transfected cells confirmed the constitutive activity of C417S and C426S mutants. These data suggest that receptor dimerization by covalent disulfide bridges alters ligand-independent as well as ligand-dependent receptor activity. Localization of the crosslink in relation to the cell membrane is important for configuration of the extracellular domain and the consecutive signal transduction.

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
cGMP-mediated signaling  IDA 1601491; 1601491 RGD 

Molecular Function
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
hormone activity  IDA 1601491 RGD 

Objects Annotated

Genes (Rattus norvegicus)
Nppc  (natriuretic peptide C)
Npr2  (natriuretic peptide receptor 2)


Additional Information