Linked Life Data

17409282

Source:http://linkedlifedata.com/resource/pubmed/id/17409282

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2007-7-9
pubmed:abstractText
Direct phosphorylation of sodium hydrogen exchanger type 3 (NHE3) is a well-established physiological phenomenon; however, the exact role of NHE3 phosphorylation in its regulation remains unclear. The objective of this study was to evaluate whether NHE3 phosphorylation at serines 552 and 605 is physiologically regulated in vivo and, if so, whether changes in phosphorylation at these sites are tightly coupled to changes in transport activity. To this end, we directly compared PKA-induced NHE3 inhibition with site-specific changes in NHE3 phosphorylation in vivo and in vitro. In vivo, PKA was activated using an intravenous infusion of parathyroid hormone in Sprague-Dawley rats. In vitro, PKA was activated directly in opossum kidney (OKP) cells using forskolin and IBMX. NHE3 activity was assayed in microvillar membrane vesicles in the rat model and by (22)Na uptake in the OKP cell model. In both cases, NHE3 phosphorylation at serines 552 and 605 was determined using previously characterized monoclonal phosphospecific antibodies directed to these sites. In vivo, we found dramatic changes in NHE3 phosphorylation at serines 552 and 605 with PKA activation but no corresponding alteration in NHE3 activity. This dissociation between NHE3 phosphorylation and activity was further verified in OKP cells in which phosphorylation clearly preceded transport inhibition. We conclude that although phosphorylation of NHE3 at serines 552 and 605 is regulated by PKA both in vivo and in vitro, phosphorylation of these sites does not directly alter Na(+)/H(+) exchange activity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1931-857X
pubmed:author
pubmed:issnType
Print
pubmed:volume
293
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
F212-8
pubmed:dateRevised
2011-4-28
pubmed:meshHeading
pubmed-meshheading:17409282-1-Methyl-3-isobutylxanthine, pubmed-meshheading:17409282-Animals, pubmed-meshheading:17409282-Cells, Cultured, pubmed-meshheading:17409282-Cyclic AMP-Dependent Protein Kinases, pubmed-meshheading:17409282-Electrophoresis, Polyacrylamide Gel, pubmed-meshheading:17409282-Forskolin, pubmed-meshheading:17409282-Kidney, pubmed-meshheading:17409282-Kidney Tubules, Proximal, pubmed-meshheading:17409282-Male, pubmed-meshheading:17409282-Microvilli, pubmed-meshheading:17409282-Parathyroid Hormone, pubmed-meshheading:17409282-Phosphodiesterase Inhibitors, pubmed-meshheading:17409282-Phosphorylation, pubmed-meshheading:17409282-Rats, pubmed-meshheading:17409282-Rats, Sprague-Dawley, pubmed-meshheading:17409282-Serine, pubmed-meshheading:17409282-Sodium, pubmed-meshheading:17409282-Sodium Radioisotopes, pubmed-meshheading:17409282-Sodium-Hydrogen Antiporter, pubmed-meshheading:17409282-Stimulation, Chemical
pubmed:year
2007
pubmed:articleTitle
NHE3 phosphorylation at serines 552 and 605 does not directly affect NHE3 activity.
pubmed:affiliation
Dept. of Pediatrics, Yale University, New Haven, CT 06520-8064, USA. hetal.kocinsky@yale.edu
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural