HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 285/4/C968    most recent 00068.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (8) Citing Articles via Google Scholar Google Scholar Articles by Vagin, O. Articles by Sachs, G. Search for Related Content PubMed PubMed Citation Articles by Vagin, O. Articles by Sachs, G.

PROTEIN AND VESICLE TRAFFICKING, CYTOSKELETON

Plasma membrane delivery of the gastric H,K-ATPase: the role of -subunit glycosylation

¹Department of Physiology, School of Medicine, University of California Los Angeles and Veterans Administration Greater Los Angeles Health Care System 90073; and ²Division of Nephrology, David Geffen School of Medicine, University of California Los Angeles Center for the Health Sciences, Los Angeles, California 90095

Submitted 20 February 2003 ; accepted in final form 20 May 2003

The factors determining trafficking of the gastric H,K-ATPase to the apical membrane remain elusive. To identify such determinants in the gastric H,K-ATPase, fusion proteins of yellow fluorescent protein (YFP) and the gastric H,K-ATPase -subunit (YFP-) and cyan fluorescent protein (CFP) and the gastric H,K-ATPase -subunit (CFP-) were expressed in HEK-293 cells. Then plasma membrane delivery of wild-type CFP-, wild-type YFP-, and YFP- mutants lacking one or two of the seven -subunit glycosylation sites was determined using confocal microscopy and surface biotinylation. Expression of the wild-type YFP- resulted in the plasma membrane localization of the protein, whereas the expressed CFP- was retained intracellularly. When coexpressed, both CFP- and YFP- were delivered to the plasma membrane. Removing each of the seven glycosylation sites, except the second one, from the extracellular loop of YFP- prevented plasma membrane delivery of the protein. Only the mutant lacking the second glycosylation site (Asn103Gln) was localized both intracellularly and on the plasma membrane. A double mutant lacking the first (Asn99Gln) and the second (Asn103Gln) glycosylation sites displayed intracellular accumulation of the protein. Therefore, six of the seven glycosylation sites in the -subunit are essential for the plasma membrane delivery of the -subunit of the gastric H,K-ATPase, whereas the second glycosylation site (Asn103), which is not conserved among the -subunits from different species, is not critical for plasma delivery of the protein.

sorting and trafficking; apical signals; plasma membrane targeting

This article has been cited by other articles:

				D. K. Y. Ang, T. C. Brodnicki, M. A. Jordan, W. E. Wilson, P. Silveira, B. L. Gliddon, A. G. Baxter, and I. R. van Driel Two genetic loci independently confer susceptibility to autoimmune gastritis Int. Immunol., September 1, 2007; 19(9): 1135 - 1144. [Abstract] [Full Text] [PDF]

				M. D. Laughery, R. J. Clifford, Y. Chi, and J. H. Kaplan Selective basolateral localization of overexpressed Na-K-ATPase beta1- and beta2- subunits is disrupted by butryate treatment of MDCK cells Am J Physiol Renal Physiol, June 1, 2007; 292(6): F1718 - F1725. [Abstract] [Full Text] [PDF]