Epithelial Domains

Philp, Nancy J.; Shoshani, Liora; Cereijido, Marcelino; Rodríguez-Boulan, Enrique

doi:10.1002/9781118015759.ch21

Cited by 6 publications

(8 citation statements)

References 103 publications

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“…This type of variation likely contributes to the variable polarity of PM proteins in different tissues, as recently reported for monocarboxylate transporters (23) (for additional discussion of this issue, see ref. 27). The results reported here are unique in demonstrating how a basolateral PM protein with a canonical YxxΦ motif is sorted along its biosynthetic and recycling and μ1B based on the known structure of μ2 indicated conservation of the tertiary structure of the pocket, with the exception of K420 in human μ2 which is replaced by P407 in μ1A and μ1B.…”

Section: Discussionmentioning

confidence: 99%

Basolateral sorting of the coxsackie and adenovirus receptor through interaction of a canonical YXXΦ motif with the clathrin adaptors AP-1A and AP-1B

Carvajal-González

Gravotta

Mattera

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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The coxsackie and adenovirus receptor (CAR) plays key roles in epithelial barrier function at the tight junction, a localization guided in part by a tyrosine-based basolateral sorting signal, 318 YNQV 321 . Sorting motifs of this type are known to route surface receptors into clathrin-mediated endocytosis through interaction with the medium subunit (μ2) of the clathrin adaptor AP-2, but how they guide new and recycling membrane proteins basolaterally is unknown. Here, we show that YNQV functions as a canonical YxxΦ motif, with both Y318 and V321 required for the correct basolateral localization and biosynthetic sorting of CAR, and for interaction with a highly conserved pocket in the medium subunits (μ1A and μ1B) of the clathrin adaptors AP-1A and AP-1B. Knock-down experiments demonstrate that AP-1A plays a role in the biosynthetic sorting of CAR, complementary to the role of AP-1B in basolateral recycling of this receptor. Our study illustrates how two clathrin adaptors direct basolateral trafficking of a plasma membrane protein through interaction with a canonical YxxΦ motif.trans-Golgi network | recycling endosomes | exocytosis | epithelial cells | protein sorting

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Section: Discussionmentioning

confidence: 99%

Basolateral sorting of the coxsackie and adenovirus receptor through interaction of a canonical YXXΦ motif with the clathrin adaptors AP-1A and AP-1B

Carvajal-González

Gravotta

Mattera

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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“…Finally, Na ϩ -K ϩ -ATPase and VSV-G travel in separate post-Golgi transport intermediates, demonstrating directly that multiple routes exist for transport from the Golgi to the basolateral membrane in polarized epithelial cells (43). Plasma membrane proteins composed of two or more subunits, such as Na-K-ATPase and monocarboxylate transporters, are challenging to study in terms of sorting mechanisms as sorting signals may be present in one or more subunits which act hierarchically and can be recognized by different components of the cellular sorting machinery (18,89).…”

Section: The Polarized Distribution Of the Na ϩ -K ϩ -Atpasementioning

confidence: 99%

The Na⁺-K⁺-ATPase as self-adhesion molecule and hormone receptor

Cereijido

Contreras

Shoshani

et al. 2012

American Journal of Physiology-Cell Physiology

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Thanks to the homeostasis of the internal milieu, metazoan cells can enormously simplify their housekeeping efforts and engage instead in differentiation and multiple forms of organization (tissues, organs, systems) that enable them to produce an astonishing diversity of mammals. The stability of the internal milieu despite drastic variations of the external environment (air, fresh or seawater, gastrointestinal fluids, glomerular filtrate, bile) is due to transporting epithelia that can adjust their specific permeability to H(2)O, H(+), Na(+), K(+), Ca(2+), and Cl(-) over several orders of magnitude and exchange substances with the outer milieu with exquisite precision. This exchange is due to the polarized expression of membrane proteins, among them Na(+)-K(+)-ATPase, an oligomeric enzyme that uses chemical energy from ATP molecules to translocate ions across the plasma membrane of epithelial cells. Na(+)-K(+)-ATPase presents two types of asymmetries: the arrangement of its subunits, and its expression in one pole of the epithelial cell ("polarity"). In most epithelia, polarity consists of the expression of Na(+)-K(+)-ATPase towards the intercellular space and arises in part from the interaction of the extracellular segment of the β-subunit with another β-subunit present in a Na(+)-K(+)-ATPase molecule expressed by a neighboring cell. In addition to enabling the Na(+)-K(+)-ATPase to transport ions and water vectorially, this position exposes its receptors to ouabain and analogous cardiotonic steroids, which are present in the internal milieu because these were secreted by endocrine cells.

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“…To explore this possibility, we first examined the effect of 10 nM ouabain on TJ and found that ouabain modifies the molecular composition and distribution pattern of specific claudins and enhances sealing of this junction (as revealed by the paracellular permeability to electrically neutral molecules and transepithelial electrical resistance, TER) [14]. Another clear demonstration of the effect of ouabain on cell-cell contacts is its modulation of ciliogenesis [15], which occurs at the culmination of the process of apical/basolateral polarization [36,37]. …”

Section: Discussionmentioning

confidence: 99%

Ouabain Increases Gap Junctional Communication in Epithelial Cells

Ponce

Larre

Castillo

et al. 2014

Cell Physiol Biochem

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Background/Aims: The finding that endogenous ouabain acts as a hormone prompted efforts to elucidate its physiological function. In previous studies, we have shown that 10 nM ouabain (i.e., a concentration within the physiological range) modulates cell-cell contacts such as tight junctions and apical/basolateral polarity. In this study, we examined whether 10 nM ouabain affects another important cell-cell feature: gap junction communication (GJC). Methods: We employed two different approaches: 1) analysis of the cell-to-cell diffusion of neurobiotin injected into a particular MDCK cell (epithelial cells from dog kidneys) in a confluent monolayer by counting the number of neighboring cells reached by the probe and 2) measurement of the electrical capacitance. Results: We found that 10 nM ouabain increase GJC by 475% within 1 hour. The Na+-K+-ATPase acts as a receptor of ouabain. In previous works we have shown that ouabain activates c-Src and ERK1/2 in 1 hour; in the present study we show that the inhibition of these proteins block the effect of ouabain on GJC. This increase in GJC does not require synthesis of new protein components, because the inhibitors cycloheximide and actinomycin D did not affect this phenomenon. Using silencing assays we also demonstrate that this ouabain-induced enhancement of GJC involves connexins 32 and 43. Conclusion: Ouabain 10 nM increases GJC in MDCK cells.

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Epithelial Domains

Cited by 6 publications

References 103 publications

Basolateral sorting of the coxsackie and adenovirus receptor through interaction of a canonical YXXΦ motif with the clathrin adaptors AP-1A and AP-1B

Basolateral sorting of the coxsackie and adenovirus receptor through interaction of a canonical YXXΦ motif with the clathrin adaptors AP-1A and AP-1B

The Na⁺-K⁺-ATPase as self-adhesion molecule and hormone receptor

Ouabain Increases Gap Junctional Communication in Epithelial Cells

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Epithelial Domains

Cited by 6 publications

References 103 publications

Basolateral sorting of the coxsackie and adenovirus receptor through interaction of a canonical YXXΦ motif with the clathrin adaptors AP-1A and AP-1B

Basolateral sorting of the coxsackie and adenovirus receptor through interaction of a canonical YXXΦ motif with the clathrin adaptors AP-1A and AP-1B

The Na+-K+-ATPase as self-adhesion molecule and hormone receptor

Ouabain Increases Gap Junctional Communication in Epithelial Cells

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Product

Resources

About

The Na⁺-K⁺-ATPase as self-adhesion molecule and hormone receptor