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The human solute carrier 26 (SLC26) gene family of anion transporters consists of 10 members (SLC26A1-A11, A10 being a pseudogene) that encode membrane glycoproteins with 14 transmembrane segments and a C-terminal cytoplasmic sulfate transporter anti-sigma antagonist domain. Thus far, mutations in eight members of the SLC26 family (A1-A6, A8, and A9) have been linked to diseases in humans. Our goal is to characterize the role of N-glycosylation and the effect of mutations in SLC26A2 and A3 proteins on their functional expression in transfected HEK-293 cells. We found that certain mutants were retained in the endoplamic reticulum via an interaction with the lectin chaperone calnexin. Some could escape protein quality control and traffic to the cell surface upon removal of the N-glycosylation sites. Furthermore, we found that loss of N-glycosylation reduced expression of SLC26A2 at the cell surface. Loss of N-glycosylation had no effect on the stability of SLC26A3, yet resulted in a profound decrease in transport activity. Thus, N-glycosylation plays three roles in the functional expression of SLC26 proteins: (1) to retain misfolded proteins in the endoplamic reticulum, (2) to stabilize the protein at the cell surface, and (3) to maintain the transport protein in a functional state. Key words: anion transport, calnexin, glycoproteins, membrane proteins, protein trafficking, solute carriers (SLC), SLC26, transporters. La famille de transporteurs d'anions SLC26 (<< solute carrier 26 >>) chez l'humain comprend 10 membres (SLC26A1-A11, A10 etant un pseudogene) qui codent des glycoproteines comportant 14 segments transmembranaires et un domaine C-terminal cytoplasmique STAS (<< sulfate transporter anti-sigma6 >>). Jusqu'a present, des mutations au sein de huit membres de la famille SLC26 (A1-A6, A8 et A9) ont ete reliees a des maladies chez l'humain. L'objectif des auteurs consiste a caracteriser le role de la N-glycosylation et l'effet des mutations de SLC26A2 et A3 sur leur expression fonctionnelle chez les cellules HEK-293 transfectees. Ils ont trouve que certains mutants etaient gardes a l'interieur du reticulum endoplasmique par leur interaction avec la calnexine, une lectine chaperon. Certains d'entre eux pouvaient echapper au controle de qualite des proteines et se rendre a la surface cellulaire a la suite de la suppression des sites de N-glycosylation. Qui plus est, ils ont trouve que la perte de N-glycosylation reduisait l'expression de SLC26A2 a la surface cellulaire. La perte de N-glycosylation n'avait pas d'effet sur la stabilite de SLC26A3, mais donnait lieu, neanmoins, a une forte diminution de l'activite de transport. Ainsi, la N-glycosylation joue trois roles dans l'expression fonctionnelle des proteines SCL26 : (1) retenir les proteines mal repliees dans le reticulum endoplasmique, (2) stabiliser la proteine a la surface cellulaire et (3) maintenir la proteine de transport dans un etat fonctionnel. [Traduit par la Redaction] Mots-cles : transport d'anion, calnexine, glycoproteines, proteines membranaires, transport des proteines, transporteurs de solutes (SLC), SLC26, transporteurs., Introduction Solute carrier (SLC) proteins comprise some 456 members subdivided into 52 families of membrane transporters that play essential roles in human health and disease. Regardless, they are one of [...]

Abstract: Bicarbonate is a simple single carbon molecule that plays surprisingly important roles in diverse biological processes. Among these are photosynthesis, the Krebs cycle, whole-body and cellular pH regulation, and [...]

The meeting 'Membrane Proteins in Health and Disease' featured 6 sessions and 2 satellite meetings. At the opening session, Gunnar von Heijne delivered a plenary lecture entitled Insertion of Membrane Proteins into the Endoplasmic Reticulum. The following session topics were Membrane Protein Trafficking and Folding, Regulation of Membrane Proteins, Membrane Protein Structure, Membrane Proteins in Diverse Species, and Membrane Proteins and Diseases. The satellite meetings discussed bicarbonate transporters and [Na.sup.+]/[H.sup.+] exchangers. Together the 21 lectures and 106 posters presented at the meeting spanned the full spectrum of current research into membrane protein structure and function. Le congres << Proteines membranaires et pathologies associees >> comportait 6 seances et 2 rencontres satellites. Lors de la seance d'ouverture, Gunnar von Heijne a presente une conference pleeniere intituleee : Insertion des proteines membranaires dans le reticulum endoplasmique. Les seances suivantes ont porte sur le trafic et le repliement des proteines membranaires, la regulation des proteines membranaires, la structure des proteines membranaires, les proteines membranaires chez differentes especes, et les proteines membranaires et les maladies. Les rencontres satellites ont permis de discuter des transporteurs du bicarbonate et des eechangeurs [Na.sup.+]/[H.sup.+]. En tout, les 21 conferences et 106 affiches presentees lors du congres ont couvert un large spectre de travaux de recherche en cours sur la structure et la fonction des proteines membranaires. [Traduit par la Redaction], 'Membrane Proteins in Health and Disease' was the topic of the 53rd Annual Meeting of the Canadian Society of Biochemistry, Molecular and Cellular Biology (CSBMCB), held at the Banff Centre [...]

The 57th Annual CSMB meeting and Conference on Membrane Proteins in Health and Disease was held 9-13 April 2014 at the Banff Centre, Banff Alberta. The meeting attracted 175 attendees [...]

The Bicarbonate Transport Meeting was held as a satellite meeting of the 53rd Annual Meeting of the Canadian Society of Biochemistry, Molecular and Cellular Biology (CSBMCB): Membrane Proteins in Health and Disease. The meeting covered the modern history of bicarbonate transporter proteins and brought together the major workers in the field. Ron Kopito recounted the story of the first determination of the amino acid sequence for a bicarbonate transporter, AE1/Band 3, 25 years earlier while working with Harvey Lodish at Harvard, while Tomohiro Yamaguchi and Teruhisa Hirai presented up-to-date data on AE1 structure obtained using electron crystallography. The meeting further spanned the spectrum of bicarbonate transporters, with sessions devoted to [Cl.sup.-]/HC[O.sub.3.sup.-] exchangers, [Na.sup.+]/HC[O.sub.3.sup.-] co-transporters, the link to carbonic anhydrase, and the SLC26 family of bicarbonate transporters expressed broadly in humans, yeast, and bacteria. Le symposium sur le transport du bicarbonate s'est tenu en tant que reunion satellite du 53ieme Congres annuel de la Societe canadienne de biochimie et de biologie moleculaire et cellulaire (SCBBMC), Proteines membranaires et pathologies associees. Le symposium a couvert l'histoire moderne des transporteurs du bicarbonate et a reuni les principaux acteurs du domaine. Ron Kopito a relate; l'historique de la premiere determination de la sequence d'acides amineisdu transporteur de bicarbonate AEl/Bande 3, 25 ans plus tot, alors qu'il travaillait avec Harvey Lodish a Harvard, tandis que Tomohiro Yamaguchi et Teruhisa Hirai ont presente les donnees les plus recentes sur la structure de AE1 obtenues par cristallographie electronique. Le symposium a couvert de maniere plus approfondie le spectre des transporteurs du bicarbonate, presentant des sessions consacrees aux echangeurs [Cl.sup.-]/HC[O.sub.3.sup.-], aux co-transporteurs [Na.sup.+]/HC[O.sub.3.sup.-], au lien a l'anhydrase carbonique, ainsi qu'a la famille SLC26 des transporteurs du bicarbonate exprimes largement chez l'humain, la levure et la bacterie. [Traduit par la Redaction], A Bicarbonate Transport Satellite Meeting organized by Joseph Casey and Reinhart Reithmeier was held at the Banff Centre, 14-15 April 2010, in advance of the 53rd Annual Meeting of the [...]