{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,22]],"date-time":"2026-01-22T17:58:09Z","timestamp":1769104689728,"version":"3.49.0"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"1","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1992,2,15]]},"abstract":"<jats:p>The Na+\/H+ exchanger is a pH-regulatory protein that extrudes one H+ ion in exchange for one Na+ ion when intracellular pH declines. A number of studies have shown phorbol ester stimulation of activity in intact cells, leading to the idea that the exchanger is regulated by protein kinase C-mediated phosphorylation in vivo. cDNA encoding the protein has been cloned, and a recent model suggests a large internal cytoplasmic C-terminal domain that may be a site of regulation of the exchanger [Sardet, Franchi &amp; Pouyssegur (1989) Cell 56, 271-280]. We examined this region of the protein using a rabbit cardiac Na+\/H+ exchanger cDNA clone. cDNA of the Na+\/H+ exchanger, coding for the C-terminal 178 amino acid residues, was cloned into the expression vector pEX-1 and expressed as a fusion protein with beta-galactosidase. The fusion protein reacted with an antibody produced against a synthetic peptide of the C-terminal 13 amino acid residues of the Na+\/H+ exchanger, confirming the identity of the expressed protein. Control and experimental pEX-1-Na+\/H+ exchanger protein was purified on a p-aminophenyl beta-D-thiogalactopyranoside-agarose column. Purified Ca2+\/calmodulin-dependent protein kinase II readily phosphorylated the Na+\/H+ exchanger protein in a Ca(2+)- and calmodulin-dependent manner in vitro, but this region of the protein was not a substrate for purified protein kinase C or for the catalytic subunit of cyclic AMP-dependent protein kinase. Control-expressed beta-galactosidase was phosphorylated to a maximal level of 0.77 +\/- 0.17 mol of Pi\/mol (mean +\/- S.E.M., n = 6) whereas the fusion protein was phosphorylated to a maximal level of 4.09 +\/- 0.39 mol of Pi\/mol (n = 6), suggesting one site of phosphorylation in beta-galactosidase and three in the C-terminal domain of the Na+\/H+ exchanger. Examination of the deduced amino acid sequence of this part of the exchanger reveals three consensus sequences for Ca2+\/calmodulin-dependent protein kinase II. These results suggest that the exchanger may be directly regulated in vivo by calmodulin-dependent protein kinase II but not by protein kinase C or cyclic AMP-dependent protein kinase.<\/jats:p>","DOI":"10.1042\/bj2820139","type":"journal-article","created":{"date-parts":[[2015,8,10]],"date-time":"2015-08-10T21:25:44Z","timestamp":1439241944000},"page":"139-145","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":77,"title":["Phosphorylation of the <i>C<\/i>-terminal domain of the Na+\/H+ exchanger by Ca2+\/calmodulin-dependent protein kinase II"],"prefix":"10.1042","volume":"282","author":[{"given":"L","family":"Fliegel","sequence":"first","affiliation":[{"name":"Department of Biochemistry and Pediatrics, Faculty of Medicine, University of Alberta, 408 Heritage Medical Research Center, Edmonton, Alberta T6G 2S2, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M P","family":"Walsh","sequence":"additional","affiliation":[{"name":"Department of Medical Biochemistry, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"D","family":"Singh","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Pediatrics, Faculty of Medicine, University of Alberta, 408 Heritage Medical Research Center, Edmonton, Alberta T6G 2S2, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"C","family":"Wong","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Pediatrics, Faculty of Medicine, University of Alberta, 408 Heritage Medical Research Center, Edmonton, Alberta T6G 2S2, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A","family":"Barr","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Pediatrics, Faculty of Medicine, University of Alberta, 408 Heritage Medical Research Center, Edmonton, Alberta T6G 2S2, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/282\/1\/139\/605710\/bj2820139.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/282\/1\/139\/605710\/bj2820139.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,24]],"date-time":"2021-11-24T00:55:47Z","timestamp":1637715347000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/282\/1\/139\/36748\/Phosphorylation-of-the-C-terminal-domain-of-the-Na"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1992,2,15]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1992,2,15]]}},"URL":"https:\/\/doi.org\/10.1042\/bj2820139","relation":{},"ISSN":["0264-6021","1470-8728"],"issn-type":[{"value":"0264-6021","type":"print"},{"value":"1470-8728","type":"electronic"}],"subject":[],"published":{"date-parts":[[1992,2,15]]}}}