Linked Life Data

11036065

Source:http://linkedlifedata.com/resource/pubmed/id/11036065

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2001-5-23
pubmed:abstractText
Nhx1, the endosomal Na(+)/H(+) exchanger of Saccharomyces cerevisiae represents the founding member of a newly emerging subfamily of intracellular Na(+)/H(+) exchangers. These proteins share significantly greater sequence homology to one another than to members of the mammalian Na(+)/H(+) exchanger (NHE) family encoding plasma membrane Na(+)/H(+) exchangers. Members of both subtypes are predicted to share a common organization, with an N-terminal transporter domain of transmembrane helices followed by a C-terminal hydrophilic tail. In the present study, we show that Nhx1 is an asparagine-linked glycoprotein and that the sites of glycosylation map to two residues within the C-terminal stretch of the polypeptide. This is the first evidence, to date, for glycosylation of the C-terminal region of any known NHE isoform. Importantly, the mapping of N-linked glycosylation to the C-terminal domain of Nhx1 is indicative of an unexpected membrane topology, particularly with regard to the orientation of the tail region. Although one recent study demonstrated that certain epitopes in the C-terminal domain of NHE3 were accessible from the exoplasmic side of the plasma membrane (Biemesderfer, D., DeGray, B., and Aronson, P. S. (1998) J. Biol. Chem. 273, 12391-12396), numerous other studies implicate a cytosolic disposition for the hydrophilic C-terminal tail of plasma membrane NHE isoforms. Our analysis of the glycosylation of Nhx1 is strongly indicative of residence of at least some portion of the hydrophilic tail domain within the endosomal lumen. These findings imply that the organization of the tail domain may be more complex than previously assumed.
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
2
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3401-7
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
The yeast Na+/H+ exchanger Nhx1 is an N-linked glycoprotein. Topological implications.
pubmed:affiliation
Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't