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Sasaki S, Shiozaki Y, Hanazaki A, Koike M, Tanifuji K, Uga M, Kawahara K, Kaneko I, Kawamoto Y, Wiriyasermkul P, Hasegawa T, Amizuka N, Miyamoto KI, Nagamori S, Kanai Y, Segawa H. Tmem174, a regulator of phosphate transporter prevents hyperphosphatemia. Sci Rep 2022; 12:6353. [PMID: 35428804 PMCID: PMC9012787 DOI: 10.1038/s41598-022-10409-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 04/05/2022] [Indexed: 11/23/2022] Open
Abstract
Renal type II sodium-dependent inorganic phosphate (Pi) transporters NaPi2a and NaPi2c cooperate with other organs to strictly regulate the plasma Pi concentration. A high Pi load induces expression and secretion of the phosphaturic hormones parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) that enhance urinary Pi excretion and prevent the onset of hyperphosphatemia. How FGF23 secretion from bone is increased by a high Pi load and the setpoint of the plasma Pi concentration, however, are unclear. Here, we investigated the role of Transmembrane protein 174 (Tmem174) and observed evidence for gene co-expression networks in NaPi2a and NaPi2c function. Tmem174 is localized in the renal proximal tubules and interacts with NaPi2a, but not NaPi2c. In Tmem174-knockout (KO) mice, the serum FGF23 concentration was markedly increased but increased Pi excretion and hypophosphatemia were not observed. In addition, Tmem174-KO mice exhibit reduced NaPi2a responsiveness to FGF23 and PTH administration. Furthermore, a dietary Pi load causes marked hyperphosphatemia and abnormal NaPi2a regulation in Tmem174-KO mice. Thus, Tmem174 is thought to be associated with FGF23 induction in bones and the regulation of NaPi2a to prevent an increase in the plasma Pi concentration due to a high Pi load and kidney injury.
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Affiliation(s)
- Sumire Sasaki
- Department of Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Yuji Shiozaki
- Department of Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Ai Hanazaki
- Department of Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Megumi Koike
- Department of Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Kazuya Tanifuji
- Department of Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Minori Uga
- Department of Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Kota Kawahara
- Department of Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Ichiro Kaneko
- Department of Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Yasuharu Kawamoto
- Department of Bio-System Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Pattama Wiriyasermkul
- Department of Laboratory Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Tomoka Hasegawa
- Developmental Biology of Hard Tissue, Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Norio Amizuka
- Developmental Biology of Hard Tissue, Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Ken-Ichi Miyamoto
- Department of Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.,Graduate School of Agriculture, Ryukoku University, Ohtsu, Japan
| | - Shushi Nagamori
- Department of Laboratory Medicine, The Jikei University School of Medicine, Tokyo, Japan.
| | - Yoshikatsu Kanai
- Department of Bio-System Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan.
| | - Hiroko Segawa
- Department of Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
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Levi M, Gratton E. Visualizing the regulation of SLC34 proteins at the apical membrane. Pflugers Arch 2019; 471:533-542. [PMID: 30613865 PMCID: PMC6436987 DOI: 10.1007/s00424-018-02249-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 12/19/2018] [Accepted: 12/20/2018] [Indexed: 10/27/2022]
Abstract
The cloning of the renal NaPi-2a (SLC34A1) and NaPi-2c (SLC34A3) phosphate transporters has made it possible to characterize the molecular and biophysical regulation of renal proximal tubular reabsorption of inorganic phosphate (Pi). Dietary factors, such as Pi and K, and several hormones and phosphatonins, including parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), and glucocorticoids, regulate the transporters through various transcriptional, translational, and post-translational mechanisms that involve acute trafficking via endocytosis or exocytosis, interactions with PDZ domain proteins, lipid microdomains, and diffusion and clustering in the apical brush border membrane. The visualization of these trafficking events by means of novel microscopy techniques that includes fluorescence lifetime imaging microscopy (FLIM), Förster resonance energy transfer (FRET), fluctuation correlation spectroscopy (FCS), and modulation tracking (MT), is the primary focus of this review.
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Affiliation(s)
- Moshe Levi
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC, USA.
| | - Enrico Gratton
- Department of Biomedical Engineering, Laboratory for Fluorescence Dynamics, University of California at Irvine, Irvine, CA, USA
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Ferreira C, Hagen P, Stern M, Hussner J, Zimmermann U, Grube M, Meyer zu Schwabedissen HE. The scaffold protein PDZK1 modulates expression and function of the organic anion transporting polypeptide 2B1. Eur J Pharm Sci 2018; 120:181-190. [DOI: 10.1016/j.ejps.2018.05.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/08/2018] [Indexed: 11/25/2022]
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4
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Yeruva S, Chodisetti G, Luo M, Chen M, Cinar A, Ludolph L, Lünnemann M, Goldstein J, Singh AK, Riederer B, Bachmann O, Bleich A, Gereke M, Bruder D, Hagen S, He P, Yun C, Seidler U. Evidence for a causal link between adaptor protein PDZK1 downregulation and Na⁺/H⁺ exchanger NHE3 dysfunction in human and murine colitis. Pflugers Arch 2014; 467:1795-807. [PMID: 25271043 PMCID: PMC4383727 DOI: 10.1007/s00424-014-1608-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 09/02/2014] [Accepted: 09/03/2014] [Indexed: 12/13/2022]
Abstract
A dysfunction of the Na(+)/H(+) exchanger isoform 3 (NHE3) significantly contributes to the reduced salt absorptive capacity of the inflamed intestine. We previously reported a strong decrease in the NHERF family member PDZK1 (NHERF3), which binds to NHE3 and regulates its function in a mouse model of colitis. The present study investigates whether a causal relationship exists between the decreased PDZK1 expression and the NHE3 dysfunction in human and murine intestinal inflammation. Biopsies from the colon of patients with ulcerative colitis, murine inflamed ileal and colonic mucosa, NHE3-transfected Caco-2BBe colonic cells with short hairpin RNA (shRNA) knockdown of PDZK1, and Pdzk1-gene-deleted mice were studied. PDZK1 mRNA and protein expression was strongly decreased in inflamed human and murine intestinal tissue as compared to inactive disease or control tissue, whereas that of NHE3 or NHERF1 was not. Inflamed human and murine intestinal tissues displayed correct brush border localization of NHE3 but reduced acid-activated NHE3 transport activity. A similar NHE3 transport defect was observed when PDZK1 protein content was decreased by shRNA knockdown in Caco-2BBe cells or when enterocyte PDZK1 protein content was decreased to similar levels as found in inflamed mucosa by heterozygote breeding of Pdzk1-gene-deleted and WT mice. We conclude that a decrease in PDZK1 expression, whether induced by inflammation, shRNA-mediated knockdown, or heterozygous breeding, is associated with a decreased NHE3 transport rate in human and murine enterocytes. We therefore hypothesize that inflammation-induced loss of PDZK1 expression may contribute to the NHE3 dysfunction observed in the inflamed intestine.
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Affiliation(s)
- Sunil Yeruva
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
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5
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Christensen EI, Wagner CA, Kaissling B. Uriniferous tubule: structural and functional organization. Compr Physiol 2013; 2:805-61. [PMID: 23961562 DOI: 10.1002/cphy.c100073] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The uriniferous tubule is divided into the proximal tubule, the intermediate (thin) tubule, the distal tubule and the collecting duct. The present chapter is based on the chapters by Maunsbach and Christensen on the proximal tubule, and by Kaissling and Kriz on the distal tubule and collecting duct in the 1992 edition of the Handbook of Physiology, Renal Physiology. It describes the fine structure (light and electron microscopy) of the entire mammalian uriniferous tubule, mainly in rats, mice, and rabbits. The structural data are complemented by recent data on the location of the major transport- and transport-regulating proteins, revealed by morphological means(immunohistochemistry, immunofluorescence, and/or mRNA in situ hybridization). The structural differences along the uriniferous tubule strictly coincide with the distribution of the major luminal and basolateral transport proteins and receptors and both together provide the basis for the subdivision of the uriniferous tubule into functional subunits. Data on structural adaptation to defined functional changes in vivo and to genetical alterations of specified proteins involved in transepithelial transport importantly deepen our comprehension of the correlation of structure and function in the kidney, of the role of each segment or cell type in the overall renal function,and our understanding of renal pathophysiology.
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Giral H, Cranston D, Lanzano L, Caldas Y, Sutherland E, Rachelson J, Dobrinskikh E, Weinman EJ, Doctor RB, Gratton E, Levi M. NHE3 regulatory factor 1 (NHERF1) modulates intestinal sodium-dependent phosphate transporter (NaPi-2b) expression in apical microvilli. J Biol Chem 2012; 287:35047-35056. [PMID: 22904329 DOI: 10.1074/jbc.m112.392415] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
P(i) uptake in the small intestine occurs predominantly through the NaPi-2b (SLC34a2) co-transporter. NaPi-2b is regulated by changes in dietary P(i) but the mechanisms underlying this regulation are largely undetermined. Sequence analyses show NaPi-2b has a PDZ binding motif at its C terminus. Immunofluorescence imaging shows NaPi-2b and two PDZ domain containing proteins, NHERF1 and PDZK1, are expressed in the apical microvillar domain of rat small intestine enterocytes. Co-immunoprecipitation studies in rat enterocytes show that NHERF1 associates with NaPi-2b but not PDZK1. In HEK co-expression studies, GFP-NaPi-2b co-precipitates with FLAG-NHERF1. This interaction is markedly diminished when the C-terminal four amino acids are truncated from NaPi-2b. FLIM-FRET analyses using tagged proteins in CACO-2(BBE) cells show a distinct phasor shift between NaPi-2b and NHERF1 but not between NaPi-2b and the PDZK1 pair. This shift demonstrates that NaPi-2b and NHERF1 reside within 10 nm of each other. NHERF1(-/-) mice, but not PDZK1(-/-) mice, had a diminished adaptation of NaPi-2b expression in response to a low P(i) diet. Together these studies demonstrate that NHERF1 associates with NaPi-2b in enterocytes and regulates NaPi-2b adaptation.
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Affiliation(s)
- Hector Giral
- Department of Medicine, University of Colorado Denver, Aurora, Colorado and the Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado 80045
| | - DeeAnn Cranston
- Department of Medicine, University of Colorado Denver, Aurora, Colorado and the Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado 80045
| | - Luca Lanzano
- Department of Biomedical Engineering, Laboratory for Fluorescence Dynamics, University of California, Irvine, California 92697
| | - Yupanqui Caldas
- Department of Medicine, University of Colorado Denver, Aurora, Colorado and the Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado 80045
| | - Eileen Sutherland
- Department of Medicine, University of Colorado Denver, Aurora, Colorado and the Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado 80045
| | - Joanna Rachelson
- Department of Medicine, University of Colorado Denver, Aurora, Colorado and the Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado 80045
| | - Evgenia Dobrinskikh
- Department of Medicine, University of Colorado Denver, Aurora, Colorado and the Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado 80045
| | - Edward J Weinman
- Department of Medicine and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - R Brian Doctor
- Department of Medicine, University of Colorado Denver, Aurora, Colorado and the Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado 80045
| | - Enrico Gratton
- Department of Biomedical Engineering, Laboratory for Fluorescence Dynamics, University of California, Irvine, California 92697
| | - Moshe Levi
- Department of Medicine, University of Colorado Denver, Aurora, Colorado and the Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado 80045.
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Yu Y, Sanderson S, Reyes M, Sharma A, Dunbar N, Srivastava T, Jüppner H, Bergwitz C. Novel NaPi-IIc mutations causing HHRH and idiopathic hypercalciuria in several unrelated families: long-term follow-up in one kindred. Bone 2012; 50:1100-6. [PMID: 22387237 PMCID: PMC3322249 DOI: 10.1016/j.bone.2012.02.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 02/09/2012] [Accepted: 02/15/2012] [Indexed: 02/06/2023]
Abstract
Homozygous and compound heterozygous mutations in SLC34A3, the gene encoding the sodium-dependent co-transporter NaPi-IIc, cause hereditary hypophosphatemic rickets with hypercalciuria (HHRH), a disorder characterized by renal phosphate-wasting resulting in hypophosphatemia, elevated 1,25(OH)(2) vitamin D levels, hypercalciuria, rickets/osteomalacia, and frequently kidney stones or nephrocalcinosis. Similar albeit less severe biochemical changes are also observed in heterozygous carriers, which are furthermore indistinguishable from those encountered in idiopathic hypercalciuria (IH). We now searched for SLC34A3 mutations (exons and introns) in two previously not reported HHRH kindreds, which resulted in the identification of three novel mutations. The affected members of kindred A were compound heterozygous for two different mutations, c.1046_47del and the intronic mutation c.560+23_561-42del, while the index case in kindred B was homozygous for the nonsense SLC34A3 mutation c.1764C>G (p.Y588X). The patient in kindred C was diagnosed with IH because of bilateral medullary nephrocalcinosis, suppressed PTH levels, and hypercalciuria; she was found to have a novel heterozygous c.1571_1880del mutation. The HHRH patients in kindred A were treated for up to 7years with oral phosphate, which led to reversal of hypophosphatemia, hypercalciuria, and prevention or healing of the mild bone abnormalities. PTH levels were normal throughout the observation period, while 1,25(OH)(2) vitamin D levels remained elevated and may thus be helpful for assessing treatment efficacy and patient compliance in HHRH.
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Affiliation(s)
- Y. Yu
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - S.R. Sanderson
- Pediatric Endocrinology, Horizon Health Network, Saint John, New Brunswick E2L 4L2, Canada
| | - M. Reyes
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - A. Sharma
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - N. Dunbar
- Pediatric Endocrinology, Baystate Medical Center, Springfield, MA 01199, USA
| | - T. Srivastava
- Bone and Mineral Disorder Clinic, Section of Pediatric Nephrology, The Children’s Mercy Hospital and Clinics, University of Missouri at Kansas City, Kansas City, MO 64108, USA
| | - H. Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - C. Bergwitz
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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Ito M, Sakurai A, Hayashi K, Ohi A, Kangawa N, Nishiyama T, Sugino S, Uehata Y, Kamahara A, Sakata M, Tatsumi S, Kuwahata M, Taketani Y, Segawa H, Miyamoto KI. An apical expression signal of the renal type IIc Na+-dependent phosphate cotransporter in renal epithelial cells. Am J Physiol Renal Physiol 2010; 299:F243-54. [PMID: 20410212 DOI: 10.1152/ajprenal.00189.2009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The type IIc Na(+)-dependent phosphate cotransporter (NaPi-IIc) is specifically targeted to, and expressed on, the apical membrane of renal proximal tubular cells and mediates phosphate transport. In the present study, we investigated the signals that determine apical expression of NaPi-IIc with a focus on the role of the N- and the C-terminal tails of mouse NaPi-IIc in renal epithelial cells [opossum kidney (OK) and Madin-Darby canine kidney cells]. Wild-type NaPi-IIc, the cotransporter NaPi-IIa, as well as several IIa-IIc chimeras and deletion mutants, were fused to enhanced green fluorescent protein (EGFP), and their cellular localization was analyzed in polarized renal epithelial cells by confocal microscopy and by cell-surface biotinylation. Fluorescent EGFP-fused NaPi-IIc transporter proteins are correctly expressed in the apical membrane of OK cells. The apical expression of N-terminal deletion mutants (deletion of N-terminal 25, 50, or 69 amino acids) was not affected by truncation. In contrast, C-terminal deletion mutants (deletion of C-terminal 45, 50, or 62 amino acids) did not have correct apical expression. A more detailed mutational analysis indicated that a domain (amino acids WLHSL) in the cytoplasmic C terminus is required for apical expression of NaPi-IIc in renal epithelial cells. We conclude that targeting of NaPi-IIc to the apical cell surface is regulated by a unique amino acid motif in the cytoplasmic C-terminal domain.
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Affiliation(s)
- Mikiko Ito
- Department of Molecular Nutrition, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Japan
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Li C, Naren AP. CFTR chloride channel in the apical compartments: spatiotemporal coupling to its interacting partners. Integr Biol (Camb) 2010; 2:161-77. [PMID: 20473396 DOI: 10.1039/b924455g] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-regulated chloride channel located primarily at the apical or luminal surfaces of epithelial cells in the airway, intestine, pancreas, kidney, sweat gland, as well as male reproductive tract, where it plays a crucial role in transepithelial fluid homeostasis. CFTR dysfunction can be detrimental and may result in life-threatening disorders. CFTR hypofunctioning because of genetic defects leads to cystic fibrosis, the most common lethal genetic disease in Caucasians, whereas CFTR hyperfunctioning resulting from various infections evokes secretory diarrhea, the leading cause of mortality in early childhood. Therefore, maintaining a dynamic balance between CFTR up-regulating processes and CFTR down-regulating processes is essential for maintaining fluid and body homeostasis. Accumulating evidence suggests that protein-protein interactions play a critical role in the fine-tuned regulation of CFTR function. A growing number of proteins have been reported to interact directly or indirectly with CFTR chloride channel, suggesting that CFTR might be coupled spatially and temporally to a wide variety of interacting partners including ion channels, receptors, transporters, scaffolding proteins, enzyme molecules, signaling molecules, and effectors. Most interactions occur primarily between the opposing terminal tails (amino or carboxyl) of CFTR protein and its binding partners, either directly or mediated through various PDZ scaffolding proteins. These dynamic interactions impact the channel function, as well as localization and processing of CFTR protein within cells. This article reviews the most recent progress and findings about the interactions between CFTR and its binding partners through PDZ scaffolding proteins, as well as the spatiotemporal regulation of CFTR-containing macromolecular signaling complexes in the apical compartments of polarized cells lining the secretory epithelia.
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Affiliation(s)
- Chunying Li
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, 540 E. Canfield Avenue, 5312 Scott Hall, Detroit, Michigan 48201, USA
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10
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Short-term regulation of organic anion transporters. Pharmacol Ther 2009; 125:55-61. [PMID: 19744520 DOI: 10.1016/j.pharmthera.2009.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 08/19/2009] [Indexed: 12/19/2022]
Abstract
Organic anion transporters (OATs), which belong to the superfamily SLC22A, are key determinants in the absorption, distribution, and excretion of a diverse array of environmental toxins, and clinically important drugs, and, therefore, are critical for the survival of mammalian species. Alteration in the function of these drug transporters plays important roles in intra- and inter-individual variability of the therapeutic efficacy and the toxicity of many drugs. As a result, the activity of OATs must be under tight regulation so as to carry out their normal functions. This review article highlights the recent advances from our laboratory as well as from others in delineating the short-term regulation of OATs. These advances provide important insights into strategies to maximize therapeutic efficacy in drug development.
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11
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Segawa H, Aranami F, Kaneko I, Tomoe Y, Miyamoto KI. The roles of Na/Pi-II transporters in phosphate metabolism. Bone 2009; 45 Suppl 1:S2-7. [PMID: 19232403 DOI: 10.1016/j.bone.2009.02.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Revised: 01/23/2009] [Accepted: 02/04/2009] [Indexed: 12/25/2022]
Abstract
The renal type II Na/Pi cotransporters, Na/Pi-IIa and Na/Pi-IIc, are expressed in the brush border membrane (BBM) of the renal proximal tubule cells. Because it has long been thought that Na/Pi-IIa alone can regulate the reabsorption of phosphate in the proximal renal tubules, Na/Pi-IIc has not been paid much attention by the renal research community. Recent studies, however, have identified Na/Pi-IIc mutations as the defective cause of hereditary hypophosphatemic rickets with hypercalciuria (HHRH). This finding indicates that Na/Pi-IIc has a rather important role in renal Pi reabsorption and bone mineralization, and that it may be a key determinant of plasma Pi concentrations in humans. Studies of Na/Pi-IIc mice indicate that Na/Pi-IIc is necessary for normal calcium homeostasis, but its role in the regulation of Pi metabolism and bone physiology may be different from that in HHRH patients. Of note, Na/Pi-IIc KO mice display abnormal vitamin D regulation without hypophosphatemia or hyperphosphaturia. Thus, Na/Pi-IIc may be involved in regulating renal vitamin D synthesis in the proximal tubular cells. The identification of proteins that interact with Na/Pi-IIc is an important area of future research. The physiologic roles of Na/Pi-IIa and Na/Pi-IIc require future elucidation.
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Affiliation(s)
- Hiroko Segawa
- Department of Molecular Nutrition, Institution of Health Biosciences, University of Tokushima Graduate School, Kuramoto-Cho 3, Tokushima 770-8503, Japan.
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12
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Chen Z, Leibiger I, Katz AI, Bertorello AM. Pals-associated tight junction protein functionally links dopamine and angiotensin II to the regulation of sodium transport in renal epithelial cells. Br J Pharmacol 2009; 158:486-93. [PMID: 19563532 DOI: 10.1111/j.1476-5381.2009.00299.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND AND PURPOSE Dopamine inhibits renal cell Na(+),K(+)-ATPase activity and cell sodium transport by promoting the internalization of active molecules from the plasma membrane, whereas angiotensin II (ATII) stimulates its activity by recruiting new molecules to the plasma membrane. They achieve such effects by activating multiple and distinct signalling molecules in a hierarchical manner. The purpose of this study was to investigate whether dopamine and ATII utilize scaffold organizer proteins as components of their signalling networks, in order to avoid deleterious cross talk. EXPERIMENTAL APPROACH Attention was focused on a multiple PDZ domain protein, Pals-associated tight junction protein (PATJ). Ectopic expression of PATJ in renal epithelial cells in culture was used to study its interaction with components of the dopamine signalling cascade. Similarly, expression of PATJ deletion mutants was employed to analyse its functional relevance during dopamine-, ATII- and insulin-dependent regulation of Na(+),K(+)-ATPase. KEY RESULTS Dopamine receptors and components of its signalling cascade mediating inhibition of Na(+),K(+)-ATPase interact with PATJ. Inhibition of Na(+),K(+)-ATPase by dopamine was prevented by expression of mutants of PATJ lacking PDZ domains 2, 4 or 5; whereas the stimulatory effect of ATII and insulin on Na(+),K(+)-ATPase was blocked by expression of PATJ lacking PDZ domains 1, 4 or 5. CONCLUSIONS AND IMPLICATIONS A multiple PDZ domain protein may add functionality to G protein-coupled and tyrosine kinase receptors signalling during regulation of Na(+),K(+)-ATPase. Signalling molecules and effectors can be integrated into a functional network by the scaffold organizer protein PATJ via its multiple PDZ domains.
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Affiliation(s)
- Z Chen
- Department of Medicine, Karolinska Institutet, Karolinska University Hospital-Solna, Stockholm, Sweden
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13
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Barros SA, Srimaroeng C, Perry JL, Walden R, Dembla-Rajpal N, Sweet DH, Pritchard JB. Activation of protein kinase Czeta increases OAT1 (SLC22A6)- and OAT3 (SLC22A8)-mediated transport. J Biol Chem 2008; 284:2672-2679. [PMID: 19028678 DOI: 10.1074/jbc.m808078200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Organic anion transporters (OATs) play a pivotal role in the clearance of small organic anions by the kidney, yet little is known about how their activity is regulated. A yeast two-hybrid assay was used to identify putative OAT3-associated proteins in the kidney. Atypical protein kinase Czeta (PKCzeta) was shown to bind to OAT3. Binding was confirmed in immunoprecipitation assays. The OAT3/PKCzeta interaction was investigated in rodent renal cortical slices from fasted animals. Insulin, an upstream activator of PKCzeta, increased both OAT3-mediated uptake of estrone sulfate (ES) and PKCzeta activity. Both effects were abolished by a PKCzeta-specific pseudosubstrate inhibitor. Increased ES transport was not observed in renal slices from OAT3-null mice. Transport of the shared OAT1/OAT3 substrate, rho-aminohippurate, behaved similarly, except that stimulation was reduced, not abolished, in the OAT3-null mice. This suggested that OAT1 activity was also modified by PKCzeta, subsequently confirmed using an OAT1-specific substrate, adefovir. Inhibition of PKCzeta also blocked the increase in ES uptake seen in response to epidermal growth factor and to activation of protein kinase A. Thus, PKCzeta acted downstream of the epidermal growth factor to protein kinase A signaling pathway. Activation of transport was accompanied by an increase in V(max) and was blocked by microtubule disruption, indicating that activation may result from trafficking of OAT3 into the plasma membrane. These data demonstrate that PKCzeta activation up-regulates OAT1 and OAT3 function, and that protein-protein interactions play a central role controlling these two important renal drug transporters.
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Affiliation(s)
- Scott A Barros
- Laboratory of Pharmacology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Chutima Srimaroeng
- Laboratory of Pharmacology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Jennifer L Perry
- Laboratory of Pharmacology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Ramsey Walden
- Laboratory of Pharmacology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Neetu Dembla-Rajpal
- Laboratory of Pharmacology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Douglas H Sweet
- Department of Pharmaceutical Sciences, Medical University of South Carolina, Charleston, South Carolina 29425
| | - John B Pritchard
- Laboratory of Pharmacology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709.
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14
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Biber J, Hernando N, Forster I, Murer H. Regulation of phosphate transport in proximal tubules. Pflugers Arch 2008; 458:39-52. [PMID: 18758808 DOI: 10.1007/s00424-008-0580-8] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 08/13/2008] [Indexed: 12/13/2022]
Abstract
Homeostasis of inorganic phosphate (P(i)) is primarily an affair of the kidneys. Reabsorption of the bulk of filtered P(i) occurs along the renal proximal tubule and is initiated by apically localized Na(+)-dependent P(i) cotransporters. Tubular P(i) reabsorption and therefore renal excretion of P(i) is controlled by a number of hormones, including phosphatonins, and metabolic factors. In most cases, regulation of P(i) reabsorption is achieved by changing the apical abundance of Na(+)/Pi cotransporters. The regulatory mechanisms involve various signaling pathways and a number of proteins that interact with Na(+)/P(i) cotransporters.
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Affiliation(s)
- J Biber
- Institute of Physiology and Zurich Center for Integrative Human Physiology, University of Zurich, Switzerland.
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15
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Ge X, Low B, Liang M, Fu J. Angiotensin II directly triggers endothelial exocytosis via protein kinase C-dependent protein kinase D2 activation. J Pharmacol Sci 2007; 105:168-76. [PMID: 17951978 DOI: 10.1254/jphs.fp0070858] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Angiotensin II (AII) has been reported to induce leukocyte adhesion to endothelium through up-regulation of P-selectin surface expression. However, the underlying molecular and cellular mechanisms remain unknown. P-selectin is stored in Weibel-Palade bodies (WPBs), large secretory granules, in endothelial cells. In this study, we examined the role of protein kinase D (PKD), a newly identified regulator of protein transport, in AII-induced WPB exocytosis and the resultant P-selectin surface expression. We demonstrated that PKD2 was rapidly activated by AII in endothelial cells through phosphorylation of the activation loop at Ser744/748. AII-induced PKD2 activation correlated with increased P-selectin surface expression. Furthermore, AII-regulated PKD2 activation is protein kinase C (PKC) alpha-dependent. Importantly, knock-down of either PKD2 or PKCalpha expression inhibited AII-mediated P-selectin surface expression and monocyte adhesion. Our findings provide the first evidence that stimulation of P-selectin surface expression via PKCalpha-dependent PKD2 activation could be an important mechanism in the early onset of AII-initiated endothelial adhesiveness.
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Affiliation(s)
- Xiaona Ge
- Center for Biomedical Research, University of Texas Health Center at Tyler, Tyler, Texas 75708, USA
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16
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Villa-Bellosta R, Barac-Nieto M, Breusegem SY, Barry NP, Levi M, Sorribas V. Interactions of the growth-related, type IIc renal sodium/phosphate cotransporter with PDZ proteins. Kidney Int 2007; 73:456-64. [PMID: 18046316 DOI: 10.1038/sj.ki.5002703] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Despite similar molecular structures, the growth-related sodium/phosphate cotransporter NaPiIIc is regulated differently than the main NaPiIIa phosphate transporter. Using two-hybrid systems and immunoprecipitation, we identified several proteins that interact with NaPiIIc that might account for this differential regulation. NaPiIIc interacted with the PDZ domain-containing sodium-hydrogen exchange-regulating factor (NHERF) 1 and NHERF3 through novel binding motifs in its C terminus. NaPiIIc from brush-border membranes coprecipitated with both NHERF1 and NHERF3, with more NHERF3 co-precipitated in rats fed a low-phosphorus diet. NaPiIIc colocalizes with both NHERF1 and NHERF3 in brush-border membranes of rats fed either a low- or high-phosphorus diet. When mouse NaPiIIc was transfected into opossum kidney cells, it was localized mainly in apical microvilli and the trans-Golgi. Both confocal and total internal reflection microscopy show that NaPiIIc colocalizes with NHERF1 and NHERF3 in the apical microvilli, and this was not altered by truncation of the last three amino acids of NaPiIIc. Interactions of NaPiIIc with NHERF1 and NHERF3 were modulated by the membrane-associated 17 kDa protein (MAP17) similarly to NaPiIIa, but only the MAP17-NaPiIIc-NHERF3 complexes were internalized to the trans-Golgi. Our study shows that NaPiIIc interacts with a limited number of PDZ domain proteins, and the mechanisms and consequences of such interactions differ from those of NaPiIIa.
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Affiliation(s)
- R Villa-Bellosta
- Laboratory of Molecular Toxicology, Department of Toxicology, University of Zaragoza, Zaragoza, Spain
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17
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Abstract
NHE3 is the brush-border (BB) Na+/H+exchanger of small intestine, colon, and renal proximal tubule which is involved in large amounts of neutral Na+absorption. NHE3 is a highly regulated transporter, being both stimulated and inhibited by signaling that mimics the postprandial state. It also undergoes downregulation in diarrheal diseases as well as changes in renal disorders. For this regulation, NHE3 exists in large, multiprotein complexes in which it associates with at least nine other proteins. This review deals with short-term regulation of NHE3 and the identity and function of its recognized interacting partners and the multiprotein complexes in which NHE3 functions.
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Affiliation(s)
- Mark Donowitz
- Department of Medicine, GI Division, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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18
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Zhou F, You G. Molecular insights into the structure-function relationship of organic anion transporters OATs. Pharm Res 2006; 24:28-36. [PMID: 17103332 DOI: 10.1007/s11095-006-9144-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Accepted: 08/02/2006] [Indexed: 12/27/2022]
Abstract
The organic anion transporter (OAT) family encoded by SLC22A mediates the absorption, distribution, and excretion of a diverse array of environmental toxins, and clinically important drugs, including anti-HIV therapeutics, anti-tumor drugs, antibiotics, anti-hypertensives, and anti-inflammatories, and therefore is critical for the survival of mammalian species. Several OATs have been identified: OAT1 (SLC22A6), OAT2 (SLC22A7), OAT3 (SLC22A8), OAT4 (SLC22A11), OAT5 (SLC22A19) OAT6 (SLC22A20) and URAT1 (SLC22A12). The expressions of these OATs have been detected in key organs such as kidney, liver, brain and placenta. OAT dysfunction in these organs may contribute to the renal, hepatic, neurological and fetal toxicity and diseases. In this review, we summarize, according to the work done by our laboratory as well as by others, the most updated molecular studies on these OAT members, especially on the aspect of their structure-function relationships. The functional roles of N-glycosylation, transmembrane domains and individual amino acids, cell surface assembly, as well as associating proteins will be discussed. In addition, we will show the recent analyses of coding region polymorphisms of OATs, which give us information on the genetic variants of OATs and their potential effects on OAT functions.
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Affiliation(s)
- Fanfan Zhou
- Department of Pharmaceutics, Rutgers, the State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA
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19
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Lanaspa MA, Giral H, Breusegem SY, Halaihel N, Baile G, Catalán J, Carrodeguas JA, Barry NP, Levi M, Sorribas V. Interaction of MAP17 with NHERF3/4 induces translocation of the renal Na/Pi IIa transporter to the trans-Golgi. Am J Physiol Renal Physiol 2006; 292:F230-42. [PMID: 16926447 DOI: 10.1152/ajprenal.00075.2006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The function of the NaPiIIa renal sodium-phosphate transporter is regulated through a complex network of interacting proteins. Several PDZ domain-containing proteins interact with its COOH terminus while the small membrane protein MAP17 interacts with its NH(2) end. To elucidate the function of MAP17, we identified its interacting proteins using both bacterial and mammalian two-hybrid systems. Several PDZ domain-containing proteins, including the four NHERF proteins, as well as NaPiIIa and NHE3, were found to bind to MAP17. The interactions of MAP17 with the NHERF proteins and with NaPiIIa were further analyzed in opossum kidney (OK) cells. Expression of MAP17 alone had no effect on the NaPiIIa apical membrane distribution, but coexpression of MAP17 and NHERF3 or NHERF4 induced internalization of NaPiIIa, MAP17, and the PDZ protein to the trans-Golgi network (TGN). This effect was not observed when MAP17 was cotransfected with NHERF1/2 proteins. Inhibition of protein kinase C (PKC) prevented expression of the three proteins in the TGN. Activation of PKC in OK cells transfected only with MAP17 induced complete degradation of MAP17 and NaPiIIa. When lysosomal degradation was prevented, both proteins accumulated in the TGN. When the dopamine D1-like receptor was activated with fenoldopam, both NaPiIIa and MAP17 also accumulated in the TGN. Finally, cotransfection of MAP17 and NHERF3 prevented the adaptive upregulation of phosphate transport activity in OK cells in response to low extracellular phosphate. Therefore, the interaction between MAP17, NHERF3/4, and NaPiIIa in the TGN could be an important intermediate or alternate path in the internalization of NaPiIIa.
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MESH Headings
- Animals
- Cells, Cultured
- Cloning, Molecular
- Cycloheximide/pharmacology
- DNA, Complementary/biosynthesis
- DNA, Complementary/genetics
- Dopamine/pharmacology
- Glutathione/metabolism
- Golgi Apparatus/metabolism
- Male
- Membrane Proteins/genetics
- Membrane Proteins/physiology
- Membranes/metabolism
- Mice
- Microscopy, Fluorescence
- Microvilli/metabolism
- Mutagenesis, Site-Directed
- Nucleic Acid Hybridization
- Opossums/metabolism
- Phosphoproteins/genetics
- Phosphoproteins/physiology
- Protein Synthesis Inhibitors/pharmacology
- Rats
- Rats, Wistar
- Sodium-Hydrogen Exchangers/genetics
- Sodium-Hydrogen Exchangers/physiology
- Sodium-Phosphate Cotransporter Proteins, Type IIa/genetics
- Sodium-Phosphate Cotransporter Proteins, Type IIa/physiology
- Subcellular Fractions/metabolism
- Transfection
- Translocation, Genetic
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Affiliation(s)
- Miguel A Lanaspa
- Laboratory of Molecular Toxicology, Univ. of Zaragoza, Veterinary Faculty, Calle Miguel Servet 177, 50013 Zaragoza, Spain
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20
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Abstract
Interaction networks, cartography and mapping, wiring and circuitry, whichever metaphor is invoked, the cardinal questions regarding cellular proteins are the same: What are they? How much is there? What do they do, and to whom do they do it? One of the more recent proteomics tools to pursue these lines of inquiry is the protein microarray, and a current report has unleashed this formidable technique upon a target of considerable biological interest, the PDZ domain family of signaling molecules.
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Affiliation(s)
- Mark R Spaller
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
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21
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Sugiura T, Kato Y, Kubo Y, Tsuji A. Mutation in an Adaptor Protein PDZKI Affects Transport Activity of Organic Cation Transporter OCTNs and Oligopeptide Transporter PEPT2. Drug Metab Pharmacokinet 2006; 21:375-83. [PMID: 17072090 DOI: 10.2133/dmpk.21.375] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Genetic polymorphisms in xenobiotic transporters have recently been clarified to be associated with change in drug distribution and disposition. To expand on recent identification of direct interaction and functional regulation of several transporters by a PDZ (PSD95, Dlg and ZO1) domain containing protein PDZK1, the effect of mutation in PDZK1 on transport activity and subcellular localization of organic cation/carnitine transporters OCTN1 and OCTN2, and oligopeptide transporter PEPT2 was examined in the present study. HEK293 cells stably expressing a mutant transcript PDZK1-E195K (HEK293/PDZK1-E195K) were constructed, followed by transient transfection of cDNA for each transporter. Uptake of tetraethylammonium by OCTN1 was much higher in HEK293/PDZK1 cells, compared with that in the parent HEK293 cells, the uptake in HEK293/PDZK1-E195K cells showing middle range between the two values. Such difference in transport activity was accounted for the difference in transport capacity, with minimal change in affinity of OCTN1 to the substrate or other compounds. The similar difference among HEK293/PDZK1, HEK293/PDZK1-E195K and HEK293 cells was also observed in transport property of OCTN2 and PEPT2, whereas the difference was not so remarkable in each transporter with the last four amino acids deleted, that has much lower interaction potential with PDZK1. Immunohistochemical analysis indicated that OCTN1 was colocalized with PDZK1 on cell-surface, whereas colocalization with PDZK1-E195K was partially observed in cytoplasmic region. These results suggest a novel hypothesis that mutation in PDZK1 potentially changes transport property of various types of xenobiotic transporters by affecting their subcellular localization, possibly leading to change in disposition of various types of substrate drugs.
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Affiliation(s)
- Tomoko Sugiura
- Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Japan
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