Immunolocalization of natriuretic peptide receptor B in the rat kidney.
The natriuretic peptide receptor (NPR) family consists of three receptor subtypes: two transmembrane forms that contain a guanylyl cyclase intracellular domain (NPR-A and NPR-B), and one truncated form (NPR-C). Because of the lack of specific agonists and antagonists for each receptor subtype and to the difficulty to detect the presence of small quantities of NPR-B by ligand binding studies, polyclonal antibodies against a peptide whose sequence was chosen from a region of the extracellular domain of rat NPR-B that is not homologous to sequences in NPR-A and NPR-C were developed. Western blotting with affinity-purified anti-NPR-B (413-426)-Tyr revealed a polypeptide of approximately 120 kD on COS-1 cell membranes transfected with rat NPR-B cDNA. The antibody recognized a second polypeptide, approximately 5 to 10 kD smaller, which probably represents the unglycosylated receptor. Anti-NPR-B (413-426)-Tyr did not show crossreactivity to any other NPR. Western blotting analysis with anti-NPR-B (413-426)-Tyr also identified a protein of appropriate size in renal vascular membranes. These results were supported by immunohistochemistry findings that demonstrated staining for NPR-B on papillary and medullary capillaries, glomeruli, and renal arteries. This study concludes that NPR-B is present in the rat kidney, although it was only detected in vascular structures.
Laboratory of Experimental Hypertension and Vasoactive Peptides, Clinical Research Institute of Montreal, Quebec, Canada.
M C
MC
Bonhomme
K L
KL
Grove
S
S
Caron
C T
CT
Crilley
G
G
Thibault
C F
CF
Deschepper
R
R
Garcia
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D006162:Guanylate Cyclase / Q000032:analysis*; D015151:Immunoblotting; D007150:Immunohistochemistry; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017461:Receptors, Atrial Natriuretic Factor / Q000032:analysis*; D012680:Sensitivity and Specificity
D006162:Guanylate Cyclase; D017461:Receptors, Atrial Natriuretic Factor; C073616:atrial natriuretic factor receptor C