Carboxypeptidase M, a Glycosylphosphatidylinositol-anchored Protein, Is Localized on Both the Apical and Basolateral Domains of Polarized Madin-Darby Canine Kidney Cells

McGwire, Gerd; Becker, Robert P.; Skidgel, Randal A.

doi:10.1074/jbc.274.44.31632

Cited by 32 publications

(30 citation statements)

References 40 publications

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“…1d). This immuno-localization reXects previous biochemical and IHC Wndings which showed that CPM is mainly found on the surface of normal pneumocytes and other epithelial cells (Skitgel et al 1998;Nagae et al 1993;McGwire et al 1999). The EGFR immunostainings were also restricted to the tumour cell membrane, though in few cases (8/52) in combination with cytoplasmic positivity.…”

Section: The Prevalance Of Cpm Expression In Lung Adenocarcinomassupporting

confidence: 84%

The presence of carboxypeptidase-M in tumour cells signifies epidermal growth factor receptor expression in lung adenocarcinomas

Tsakiris

Soós

Nemes

et al. 2007

J Cancer Res Clin Oncol

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Section: The Prevalance Of Cpm Expression In Lung Adenocarcinomassupporting

confidence: 84%

The presence of carboxypeptidase-M in tumour cells signifies epidermal growth factor receptor expression in lung adenocarcinomas

Tsakiris

Soós

Nemes

et al. 2007

J Cancer Res Clin Oncol

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“…Several results obtained suggest that these chimeras were targeted for lysosomal instead of the endoplasmic reticulumassociated degradation (ERAD). First, the AQP-specific bands detected on blot (16,29,32,35,38, and 40 kDa) are different from those always observed for ER-retained mutants (29 and 32 kDa) ( Fig. 3C; Refs.…”

Section: The Aqp2 Nh 2 Terminus Makes Chimeras Prone To Degradationmentioning

confidence: 99%

Role of cytoplasmic termini in sorting and shuttling of the aquaporin-2 water channel

Balkom¹,

Graat²,

Raak³

et al. 2004

American Journal of Physiology-Cell Physiology

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of cytoplasmic termini in sorting and shuttling of the aquaporin-2 water channel. Am J Physiol Cell Physiol 286: C372-C379, 2004. First published October 15, 2003 10.1152/ajpcell.00271.2003.-In mammals, the regulation of water homeostasis is mediated by the aquaporin-1 (AQP1) water channel, which localizes to the basolateral and apical membranes of the early nephron segment, and AQP2, which is translocated from intracellular vesicles to the apical membrane of collecting duct cells after vasopressin stimulation. Because a similar localization and regulation are observed in transfected Madin-Darby Canine Kidney (MDCK) cells, we investigated which segments of AQP2 are important for its routing to forskolin-sensitive vesicles and the apical membrane through analysis of AQP1-AQP2 chimeras. AQP1 with the entire COOH tail of AQP2 was constitutively localized in the apical membrane, whereas chimeras with shorter COOH tail segments of AQP2 were localized in the apical and basolateral membrane. AQP1 with the NH2 tail of AQP2 was constitutively localized in both plasma membranes, whereas AQP1 with the NH2 and COOH tail of AQP2 was sorted to intracellular vesicles and translocated to the apical membrane with forskolin. These data indicate that region N220-S229 is essential for localization of AQP2 in the apical membrane and that the NH2 and COOH tail of AQP2 are essential for trafficking of AQP2 to intracellular vesicles and its shuttling to and from the apical membrane. routing signals; chimera; Madin-Darby canine kidney cells; regulated trafficking TO MAINTAIN WATER AND OSMOLYTE BALANCE, the human kidney daily forms 180 l of pro-urine. The main portion of the water from the pro-urine is reabsorbed, which occurs mainly through aquaporin-1 (AQP1) and AQP2 (9, 10, 35). AQP1, responsible for 90% of the water reabsorption, is constitutively present in the apical and basolateral membrane of proximal tubules and the descending limbs of Henle (40). The fine-tuning of water reabsorption takes place in the renal collecting duct and is regulated by the antidiuretic hormone arginine vasopressin (AVP). After release of AVP by the pituitary gland and binding to its type-2 receptor (V2R) in the basolateral membrane of collecting duct principal cells, an intracellular cAMP signaling cascade is initiated, resulting in the phosphorylation of AQP2 and its redistribution from vesicles to the apical membrane. Then, driven by an osmotic gradient, collecting duct water uptake and urine concentration is initiated via AQP2 in the apical and AQP3/AQP4 in the basolateral membranes (11, 37). Removal of AVP reverses this translocation process, restoring the water-impermeable state of the apical membrane (7,23,26). A proper regulation of AQP2 sorting and translocation to the apical membrane is thus of critical importance for human water homeostasis. At present, however, it is unclear which protein segments of AQP2 are critical for this regulation.All AQPs are homotetrameric integral membrane proteins, consisting of subunits of about 30 kDa, which pas...

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“…This was done to compare association of both tracers on the same basis. Selective uptake is defined as Biotinylation of SR-BI and SR-BII-Biotinylation was carried out as described elsewhere (28), with slight modifications. CHO cells were incubated in serum-free Ham's F-12 medium with 0.5% BSA for 2 h prior to the experiment.…”

Section: Methodsmentioning

confidence: 99%

High Density Lipoprotein Uptake by Scavenger Receptor SR-BII

Eckhardt

Cai

Sun

et al. 2004

Journal of Biological Chemistry

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Scavenger receptor class B, type I (SR-BI) mediates selective uptake of high density lipoprotein (HDL) lipids. It is unclear whether this process occurs at the cell membrane or via endocytosis. Our group previously identified an alternative mRNA splicing variant of SR-BI, named SR-BII, with an entirely different, yet highly conserved cytoplasmic C terminus. In this study we aimed to compare HDL uptake by both isoforms. Whereas SR-BI was mainly (ϳ70%) localized on the surface of transfected Chinese hamster ovary cells, as determined by biotinylation, HDL binding at 4°C, and studies of enhanced green fluorescent protein-tagged SR-BI/II fusion proteins, the majority of SR-BII (ϳ80 -90%) was expressed intracellularly. The cellular distribution of SR-BI was not affected by deletion of the C terminus, which suggests that the distinct C terminus of SR-BII is responsible for its intracellular expression. Pulse-chase experiments showed that SR-BII rapidly internalized HDL protein, whereas in the case of SR-BI most HDL protein remained surface bound. Like its ligand, SR-BII was more rapidly endocytosed compared with SR-BI. Despite more rapid HDL uptake by SR-BII than SR-BI, selective cholesteryl ether uptake was significantly lower. Relative to their levels of expression at the cell surface, however, both isoforms mediated selective uptake with similar efficiency. HDL protein that was internalized by SR-BII largely co-localized with transferrin in the endosomal recycling compartment. Within the endosomal recycling compartment of SR-BII cells, there was extensive co-localization of internalized HDL lipid and protein. These results do not support a model that selective lipid uptake by SR-BI requires receptor/ligand recycling within the cell. We conclude that SR-BII may influence cellular cholesterol trafficking and homeostasis in a manner that is distinct from SR-BI.

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Carboxypeptidase M, a Glycosylphosphatidylinositol-anchored Protein, Is Localized on Both the Apical and Basolateral Domains of Polarized Madin-Darby Canine Kidney Cells

Cited by 32 publications

References 40 publications

The presence of carboxypeptidase-M in tumour cells signifies epidermal growth factor receptor expression in lung adenocarcinomas

The presence of carboxypeptidase-M in tumour cells signifies epidermal growth factor receptor expression in lung adenocarcinomas

Role of cytoplasmic termini in sorting and shuttling of the aquaporin-2 water channel

High Density Lipoprotein Uptake by Scavenger Receptor SR-BII

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