Myo-inositol and betaine transporters regulated by tonicity are basolateral in MDCK cells

Yamauchi, Atsushi; Kwon, H. Moo; Uchida, Shinichi; Preston, A.; Handler, Jerome S.

doi:10.1152/ajprenal.1991.261.1.f197

Cited by 60 publications

(79 citation statements)

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“…Glycine uptake was performed at room temperature according to a modification of the method of Yamauchi et al (29). After one wash of each chamber with complete phosphate-buffered saline (PBS/Ca/Mg: 137 mM NaCl, 2.7 mM KCl, 0.89 mM CaCl 2 , 0.49 mM MgCl 2 , 4.3 mM Na 2 HPO 4 ⅐7H 2 O, 1.4 mM KH 2 PO 4 , pH 7.3) and another wash with uptake buffer (150 mM NaCl, 5 mM KCl, 1 mM MgCl 2, 1 mM CaCl 2, 10 mM D(ϩ)-glucose, 10 mM HEPES-Tris, pH 7.4), the cells were incubated with 0.2 M [ 3 H]glycine in uptake buffer either in the upper or in the lower chamber for 10 min.…”

Section: Methodsmentioning

confidence: 99%

The Role of N-Glycosylation in Transport to the Plasma Membrane and Sorting of the Neuronal Glycine Transporter GLYT2

Maza¹,

Poyatos²,

López-Corcuera

et al. 2001

Journal of Biological Chemistry

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Section: Methodsmentioning

confidence: 99%

The Role of N-Glycosylation in Transport to the Plasma Membrane and Sorting of the Neuronal Glycine Transporter GLYT2

Maza¹,

Poyatos²,

López-Corcuera

et al. 2001

Journal of Biological Chemistry

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“…Like taurine, betaine accumulation by MDCK cells is primarily localized to the basolateral surface (20). Kinetic analysis reveals the presence of two distinct transport systems for betaine, a high-affinity system and a low-affinity system (20).…”

Section: Effect Of Other Osmolytes and Amino Acids On The Ability Of mentioning

confidence: 99%

The Relative Roles of External Taurine Concentration and Medium Osmolality in the Regulation of Taurine Transport in LLC-PK1 and MDCK Cells

1995

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Taurine is a l3-sulfonic amino acid that serves as a nutrient important for developing brain and retina and as an osmolyte in the medullary collecting duct. The activity of the taurine transport system is regulated by substrate supply and by the external osmolality; these two stimuli induce changes in taurine transport. Increased medium osmolality (500 mosmol) stimulates taurine uptake into MDCK cells but not LLC-PKI cells. The enhanced taurine uptake that occurs in response to hyperosmolality is localized primaril y to the basolateral surface of MOCK cells, whereas the adapti ve response to medium taurine concentration is expressed on both the apical and the basolateral surfaces of both cell lines. The response of MOCK cells to medium osmolality requires protein synthesis and RNA transcription and is expressed in the presence of microtubular toxins. When cell monolayers were loaded with taurine by incubation in hightaurine medium before increasing medium osmolality, the expected increase in taurine uptake was blunted. Similarly, increased external l3-alanin e (500 p,M) also prevented the anticipated increase in taurine accumulation in response to hypertonicity; aminoisobutyric acid and betaine (500 p,M) partially prevented the increase in taurine transport after hypertonicity, T aurine, a f3-sulfonic am ino aci d that is found in millimol ar intrac ellular concentrati ons in the kidney o f many mammali an sp eci es, is pos tulated to ha ve several ke y functions in th e kidney ; among these are th e fun cti on of a nutritional substrat e, as w ell as that of an osmolyt e (1) . T aurine is tran sported b y the ren al tubular cell b y a sodium-and chlo ride-depe ndent tran sporter, w hich ac cepts the f3-amino aci d taurine and stru ctural ana lo gs such as f3-alanine (2-5) .Received April 26, 1994; accepted September 20, 1994 whereas L-alanine had no effect. The concentration of taurine or structurally similar analogs in the external medium might modify the response of taurine accumulation after exposure to hypertonic medium, in that taurine-replete cells behave differently than taurine-depleted cells. These studies indicate that there are at least two distinct mechanisms involved in the regulation of taurine transport: external taurine concentration and medium osmolality, with taurine concentration seeming to be the predominant stimulus. Thus, the changes in cell taurine transport depend on the physiologic stimulus as well as the cell studied, a phenomenon that might be related to the renal tubular site of origin. The kidney taurine tran sp orter serves at least tw o im po rta nt function s: 1) to reab sorb filte red taurine as a nutrient (this occurs in the proximal tubule and has been shown to be fun cti on all y immature in the neon at al rat, to be regulated by dietary taurine intake, and to be abnormal in the hypertaurininur ic mouse model) and 2) to offe r protection to medullary coll ecting du ct cell s or to MDCK (M ad in-Darby canine kidne y) cells in response to increased external os mola lity by se r...

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“…The transporter was cloned from Madin-Darby canine kidney (MDCK) cells (1); BGT1 transport activity is low in MDCK cells maintained in isotonic medium but greatly induced in response to prolonged hypertonic stress. Transcription plays a major role in this stimulation, leading to increased BGT1 mRNA levels and consequently increased transport activity (1,2). However, it has been suggested that the post-transcriptional regulation of BGT1 protein also plays a role in cell adaptation to hypertonic stress (3).…”

mentioning

confidence: 99%

Protein Kinase C-mediated Phosphorylation of the BGT1 Epithelial γ-Aminobutyric Acid Transporter Regulates Its Association with LIN7 PDZ Proteins

Massari

Vanoni

Longhi

et al. 2005

Journal of Biological Chemistry

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The Na/Cl-dependent BGT1 transporter has osmoprotective functions by importing the small osmolyte betaine into the cytosol of renal medullary epithelial cells. We have demonstrated previously that the surface localization of the transporter in Madin-Darby canine kidney cells depends on its association with the LIN7 PDZ protein through a PDZ target sequence in the last 5 residues of the transporter (-KETHL). Here we describe a protein kinase C (PKC)-mediated mechanism regulating the association between BGT1 and LIN7. Reduced transport activity paralleled by the intracellular relocalization of the transporter was observed in response to the PKC activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment. This activation caused clathrindependent internalization of the transporter and its targeting to a recycling compartment that contains the truncated transporter lacking the LIN7 binding motif (BGT⌬5) but not the LIN7 partner of BGT1. The decreased association between BGT1 and LIN7 was demonstrated further by coimmunoprecipitation studies and in vitro binding to recombinant LIN7 fusion protein.The TPA treatment induced phosphorylation of surface BGT1 on serine and threonine residues. However, a greater increase in phosphothreonines than phosphoserines was measured in the wild type transporter, whereas the opposite was true in the BGTSer mutant in which a serine replaced the threonine 612 in the LIN7 association motif (-KESHL). No similar increase in relative phosphoserines or phosphothreonines was found in the BGT⌬5 transporter. Moreover, phosphorylation of threonine 612 in a BGT COOH-terminal peptide impaired its association with recombinant LIN7. Taken together, these data demonstrate that the post-translational regulation of BGT1 surface density is a result of transporter phosphorylation and that threonine 612 is an essential residue in this PKC-mediated regulation.

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Myo-inositol and betaine transporters regulated by tonicity are basolateral in MDCK cells

Cited by 60 publications

References 0 publications

The Role of N-Glycosylation in Transport to the Plasma Membrane and Sorting of the Neuronal Glycine Transporter GLYT2

The Role of N-Glycosylation in Transport to the Plasma Membrane and Sorting of the Neuronal Glycine Transporter GLYT2

The Relative Roles of External Taurine Concentration and Medium Osmolality in the Regulation of Taurine Transport in LLC-PK1 and MDCK Cells

Protein Kinase C-mediated Phosphorylation of the BGT1 Epithelial γ-Aminobutyric Acid Transporter Regulates Its Association with LIN7 PDZ Proteins

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