Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2003-1-28
pubmed:abstractText
We studied hyperosmolarity-induced changes in cell volume and cytoplasmic pH in PS120 cells expressing Na(+)/H(+) exchanger (NHE) isoforms and their mutants. Change in cell volume was estimated by measuring change in cell height by means of confocal microscopy. Regulatory volume increase (RVI) and cytoplasmic alkalinization were observed in cells expressing NHE1 but not in cells expressing NHE2 or NHE3. Studies using chimeric exchangers revealed that the membrane domain of the exchanger is responsible for the difference in volume sensitivity between NHE1 and NHE2. Although deletion or point mutation within the first extracellular loop of NHE1 did not affect RVI and alkalinization, point mutations within the corresponding region of NHE2, particularly a region containing aa 41-53, as well as replacement of the N-terminus of NHE2 with the corresponding region of NHE1, rendered NHE2 responsive to the activating effect of cell shrinkage. Thus, the membrane domain plays an important role in the response of the exchanger to cell shrinkage. The data suggest that the putative first extracellular loop of NHE2, but not that of NHE1, may exert an inhibitory influence on hyperosmolarity-induced activation of the exchanger and thereby block RVI.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1086-94
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:12549930-Amino Acid Sequence, pubmed-meshheading:12549930-Animals, pubmed-meshheading:12549930-Cell Adhesion, pubmed-meshheading:12549930-Cell Line, pubmed-meshheading:12549930-Cell Size, pubmed-meshheading:12549930-Cricetinae, pubmed-meshheading:12549930-Extracellular Space, pubmed-meshheading:12549930-Humans, pubmed-meshheading:12549930-Hydrogen-Ion Concentration, pubmed-meshheading:12549930-Intracellular Fluid, pubmed-meshheading:12549930-Molecular Sequence Data, pubmed-meshheading:12549930-Mutagenesis, Site-Directed, pubmed-meshheading:12549930-Osmotic Pressure, pubmed-meshheading:12549930-Protein Isoforms, pubmed-meshheading:12549930-Protein Structure, Tertiary, pubmed-meshheading:12549930-Rats, pubmed-meshheading:12549930-Recombinant Fusion Proteins, pubmed-meshheading:12549930-Sodium-Hydrogen Antiporter, pubmed-meshheading:12549930-Transfection
pubmed:year
2003
pubmed:articleTitle
Evidence for involvement of the putative first extracellular loop in differential volume sensitivity of the Na+/H+ exchangers NHE1 and NHE2.
pubmed:affiliation
Department of Molecular Physiology, National Cardiovascular Center Research Institute, Fujishirodai 5-7-1, Suita, Osaka 565-8565, Japan.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't