Atrial natriuretic peptide-stimulated Ca2+ reabsorption in rabbit kidney requires membrane-targeted, cGMP-dependent protein kinase type II.
Atrial natriuretic peptide (ANP) and nitric oxide (NO) are key regulators of ion and water transport in the kidney. Here, we report that these cGMP-elevating hormones stimulate Ca2+ reabsorption via a novel mechanism specifically involving type II cGMP-dependent protein kinase (cGK II). ANP and the NO donor, sodium nitroprusside (SNP), markedly increased Ca2+ uptake in freshly immunodissected rabbit connecting tubules (CNT) and cortical collecting ducts (CCD). Although readily increasing cGMP, ANP and SNP did not affect Ca2+ and Na+ reabsorption in primary cultures of these segments. Immunoblot analysis demonstrated that cGK II, and not cGK I, was present in freshly isolated CNT and CCD but underwent a complete down-regulation during the primary cell culture. However, upon adenoviral reexpression of cGK II in primary cultures, ANP, SNP, and 8-Br-cGMP readily increased Ca2+ reabsorption. In contrast, no cGMP-dependent effect on electrogenic Na+ transport was observed. The membrane localization of cGK II proved to be crucial for its action, because a nonmyristoylated cGK II mutant that was shown to be localized in the cytosol failed to mediate ANP-stimulated Ca2+ transport. The Ca2+-regulatory function of cGK II appeared isotype-specific because no cGMP-mediated increase in Ca2+ transport was observed after expression of the cytosolic cGK Ibeta or a membrane-bound cGK II/Ibeta chimer. These results demonstrate that ANP- and NO-stimulated Ca2+ reabsorption requires membrane-targeted cGK II.
Hoenderop
J G
JG
Department of Biochemistry, Institute of Cellular Signaling University of Nijmegen, P.O. Box 9101, NL-6500 HB Nijmegen, The Netherlands. J.Hoenderop@bioch.kun.nl
Vaandrager
A B
AB
Dijkink
L
L
Smolenski
A
A
Gambaryan
S
S
Lohmann
S M
SM
de Jonge
H R
HR
Willems
P H
PH
Bindels
R J
RJ
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology*; D002478:Cells, Cultured; D062967:Cyclic GMP-Dependent Protein Kinase Type II; D017869:Cyclic GMP-Dependent Protein Kinases / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D007672:Kidney Cortex / Q000187:drug effects / Q000378:metabolism*; D007684:Kidney Tubules / Q000187:drug effects / Q000378:metabolism*; D007685:Kidney Tubules, Collecting / Q000187:drug effects / Q000378:metabolism; D007700:Kinetics; D011817:Rabbits; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion
D011994:Recombinant Proteins; D009320:Atrial Natriuretic Factor; D062967:Cyclic GMP-Dependent Protein Kinase Type II; D017869:Cyclic GMP-Dependent Protein Kinases; C569729:PRKG2 protein, human; C569732:Prkg2 protein, rat; D002118:Calcium