Unravelling protein sorting

Nelson, W. James; Rodríguez-Boulan, Enrique

doi:10.1038/ncb0404-282

Cited by 19 publications

(23 citation statements)

References 15 publications

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“…They can be sorted within the trans-Golgi network (TGN) 1 into specific containers, which are then delivered directly either to the apical or basolateral membranes (1)(2)(3)(4)(5). Alternatively, they are initially delivered first to one membrane (e.g.…”

mentioning

confidence: 99%

“…the apical membrane). This latter indirect process has been termed transcytosis (3)(4)(5). Both of these direct and indirect pathways are regulated.…”

mentioning

confidence: 99%

“…Both of these direct and indirect pathways are regulated. Specific machinery essential for the sorting process is present within the cell and recognizes sorting signals such as minimal amino acid motifs, carbohydrate or lipid moieties, embedded within individual proteins (1)(2)(3)(4)(5). Apical sorting signals are usually found in the ectodomain or the transmembrane domain of proteins and may include glycosylphosphatidylinositol anchors, N-and O-linked glycans, and transmembrane anchor signals (1)(2)(3)(4)(5).…”

mentioning

confidence: 99%

“…Specific machinery essential for the sorting process is present within the cell and recognizes sorting signals such as minimal amino acid motifs, carbohydrate or lipid moieties, embedded within individual proteins (1)(2)(3)(4)(5). Apical sorting signals are usually found in the ectodomain or the transmembrane domain of proteins and may include glycosylphosphatidylinositol anchors, N-and O-linked glycans, and transmembrane anchor signals (1)(2)(3)(4)(5). Basolateral sorting signals are usually found within the juxtamembrane cytoplasmic region of membrane proteins and include tyrosine-based and dileucine-based motifs (1)(2)(3)(4)(5).…”

mentioning

confidence: 99%

“…Apical sorting signals are usually found in the ectodomain or the transmembrane domain of proteins and may include glycosylphosphatidylinositol anchors, N-and O-linked glycans, and transmembrane anchor signals (1)(2)(3)(4)(5). Basolateral sorting signals are usually found within the juxtamembrane cytoplasmic region of membrane proteins and include tyrosine-based and dileucine-based motifs (1)(2)(3)(4)(5). Several different sorting signals can be present in a protein, but they may vary in their importance in the targeting process.…”

mentioning

confidence: 99%

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Use of the H,K-ATPase β Subunit to Identify Multiple Sorting Pathways for Plasma Membrane Delivery in Polarized Cells

Vagin

Turdikulova

Yakubov

et al. 2005

Journal of Biological Chemistry

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A dynamic equilibrium between multiple sorting pathways maintains polarized distribution of plasma membrane proteins in epithelia. To identify sorting pathways for plasma membrane delivery of the gastric H,K-ATPase ␤ subunit in polarized cells, the protein was expressed as a yellow fluorescent protein N-terminal construct in Madin-Darby canine kidney (MDCK) and LLC-PK1 cells. Confocal microscopy and surface-selective biotinylation showed that 80% of the surface amount of the ␤ subunit was present on the apical membrane in LLC-PK1 cells, but only 40% was present in MDCK cells. Nondenaturing gel electrophoresis of the isolated membranes showed that a significant fraction of the H,K-ATPase ␤ subunits associate with the endogenous Na,K-ATPase ␣ 1 subunits in MDCK but not in LLC-PK cells. Hence, co-sorting of the H,K-ATPase ␤ subunit with the Na,K-ATPase ␣ 1 subunit to the basolateral membrane in MDCK cells may determine the differential distribution of the ␤ subunit in these two cell types. The major fraction of unassociated monomeric H,K-ATPase ␤ subunits is detected in the apical membrane. Quantitative analysis showed that half of the apical pool of the ␤ subunit originates directly from the trans-Golgi network and the other half from transcytosis via the basolateral membrane in MDCK cells. A minor fraction of monomeric ␤ subunits detected in the basolateral membrane represents a transient pool of the protein that undergoes transcytosis to the apical membrane. Hence, the steady state distribution of the H,K-ATPase ␤ subunit in polarized cells depends on the balance between (a) direct sorting from the trans-Golgi network, (b) secondary associative sorting with a partner protein, and (c) transcytosis.

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mentioning

confidence: 99%

“…the apical membrane). This latter indirect process has been termed transcytosis (3)(4)(5). Both of these direct and indirect pathways are regulated.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Use of the H,K-ATPase β Subunit to Identify Multiple Sorting Pathways for Plasma Membrane Delivery in Polarized Cells

Vagin

Turdikulova

Yakubov

et al. 2005

Journal of Biological Chemistry

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Cytoskeleton Dynamics in Health and Disease: Role of Molecular Switches and Rheostats

Osman

2015

The Cytoskeleton in Health and Disease

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Polarized membrane distribution of potassium-dependent ion pumps in epithelial cells: Different roles of the N-glycans of their β subunits

Vagin

Turdikulova

Tokhtaeva

2007

Cell Biochem Biophys

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The Na,K-ATPases and the H,K-ATPases are two potassium-dependent homologous heterodimeric P2-type pumps that catalyze active transport of Na+ in exchange for K+ (Na,K-ATPase) or H+ in exchange for K+ (H,K-ATPase). The ubiquitous Na,K-ATPase maintains intracellular ion balance and membrane potential. The gastric H,K-ATPase is responsible for acid secretion by the parietal cell of the stomach. Both pumps consist of a catalytic alpha-subunit and a glycosylated beta-subunit that is obligatory for normal pump maturation and trafficking. Individual N-glycans linked to the beta-subunits of the Na,K-ATPase and H,K-ATPase are important for stable membrane integration of their respective alpha subunits, folding, stability, subunit assembly, and enzymatic activity of the pumps. They are also essential for the quality control of unassembled beta-subunits that results in either the exit of the subunits from the ER or their ER retention and subsequent degradation. Overall, the importance of N-glycans for the maturation and quality control of the H,K-ATPase is greater than that of the Na,K-ATPase. The roles of individual N-glycans of the beta-subunits in the post-ER trafficking, membrane targeting and plasma membrane retention of the Na,K-ATPase and H,K-ATPase are different. The Na,K-ATPase beta1-subunit is the major beta-subunit isoform in cells with lateral location of the pump. All three N-glycans of the Na,K-ATPase beta1-subunit are important for the lateral membrane retention of the pump due to glycan-mediated interaction between the beta1-subunits of the two neighboring cells in the cell monolayer and cytosolic linkage of the alpha-subunit to the cytoskeleton. This intercellular beta1-beta1 interaction is also important for formation of cell-cell contacts. In contrast, the N-glycans unique to the Na,K-ATPase beta2-subunit,which has up to eight N-glycosylation sites, contain apical sorting information. This is consistent with the apical location of the Na,K-ATPase in normal and malignant epithelial cells with high abundance of the beta2-subunit. Similarly, all seven N-glycans of the gastric H,K-ATPase beta-subunit determine apical sorting of this subunit.

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Unravelling protein sorting

Cited by 19 publications

References 15 publications

Use of the H,K-ATPase β Subunit to Identify Multiple Sorting Pathways for Plasma Membrane Delivery in Polarized Cells

Use of the H,K-ATPase β Subunit to Identify Multiple Sorting Pathways for Plasma Membrane Delivery in Polarized Cells

Cytoskeleton Dynamics in Health and Disease: Role of Molecular Switches and Rheostats

Polarized membrane distribution of potassium-dependent ion pumps in epithelial cells: Different roles of the N-glycans of their β subunits

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