Linked Life Data

9933588

Source:http://linkedlifedata.com/resource/pubmed/id/9933588

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1999-3-11
pubmed:abstractText
Regulation of the renal Na/H exchanger NHE-3 by protein kinase A (PKA) is a key intermediate step in the hormonal regulation of acid-base and salt balance. We studied the role of NHE-3 phosphorylation in this process in NHE-deficient AP-1 cells transfected with NHE-3 and in OKP cells expressing native NHE-3. A dominant-negative PKA-regulatory subunit completely abolished the effect of cAMP on NHE-3 activity demonstrating a role of PKA in the functional regulation of NHE-3 by cAMP. NHE-3 isolated from cAMP-treated cells showed lower phosphorylation by purified PKA in vitro suggesting that NHE-3 is a PKA substrate in vivo. Although changes in NHE-3 whole protein phosphorylation is difficult to detect in response to cAMP addition, the tryptic phosphopeptide map of in vivo phosphorylated NHE-3 showed a complex pattern of constitutive and cAMP-induced phosphopeptides. To test the causal relationship between phosphorylation and activity, we mutated eight serines in the cytoplasmic domain to glycine or alanine. Single or multiple mutants harboring S552A or S605G showed no PKA activation or reduced regulation by PKA activation. Ser-552 and Ser-605 were phosphorylated in vivo. However, multiple mutations of serines other than Ser-552 or Ser-605 also reduced the functional PKA regulation. We conclude that regulation of NHE-3 by PKA in vivo involves complex mechanisms, which include phosphorylation of Ser-552 and Ser-605.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
274
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3978-87
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Acute inhibition of Na/H exchanger NHE-3 by cAMP. Role of protein kinase a and NHE-3 phosphoserines 552 and 605.
pubmed:affiliation
The Department of Internal Medicine,University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.