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Hartmann C, Thüring EM, Greune L, Michels BE, Pajonczyk D, Leußink S, Brinkmann F, Glaesner-Ebnet M, Wardelmann E, Zobel T, Schmidt MA, Janssen KP, Gerke V, Ebnet K. Intestinal brush border formation requires a TMIGD1-based intermicrovillar adhesion complex. Sci Signal 2022; 15:eabm2449. [PMID: 36099341 DOI: 10.1126/scisignal.abm2449] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Intestinal epithelial cells absorb nutrients through the brush border, composed of dense arrays of highly ordered microvilli at their apical membranes. A protocadherin-based intermicrovillar adhesion complex localized at microvilli tips mediates microvilli packing and organization. Here, we identified a second adhesion complex localized at the proximal base region of microvilli. This complex contained the immunoglobulin superfamily member TMIGD1, which directly interacted with the microvillar scaffolding proteins EBP50 and E3KARP. Complex formation with EBP50 required the activation of EBP50 by the actin-binding protein ezrin and was enhanced by the dephosphorylation of Ser162 in the PDZ2 domain of EBP50 by the phosphatase PP1α. Binding of the EBP50-ezrin complex to TMIGD1 enhanced the dynamic turnover of EBP50 at microvilli. Enterocyte-specific inactivation of Tmigd1 in mice resulted in microvillar blebbing, loss of intermicrovillar adhesion, and perturbed brush border formation. Thus, we identified a second adhesion complex in microvilli and propose a mechanism that promotes microvillar formation and dynamics.
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Affiliation(s)
- Christian Hartmann
- Institute-associated Research Group "Cell adhesion and cell polarity", ZMBE, University of Münster, D-48149 Münster, Germany.,Institute of Medical Biochemistry, ZMBE, University of Münster, D-48149 Münster, Germany
| | - Eva-Maria Thüring
- Institute-associated Research Group "Cell adhesion and cell polarity", ZMBE, University of Münster, D-48149 Münster, Germany.,Institute of Medical Biochemistry, ZMBE, University of Münster, D-48149 Münster, Germany
| | - Lilo Greune
- Institute of Infectiology, ZMBE, University of Münster, D-48149 Münster, Germany
| | - Birgitta E Michels
- Institute-associated Research Group "Cell adhesion and cell polarity", ZMBE, University of Münster, D-48149 Münster, Germany.,Institute of Medical Biochemistry, ZMBE, University of Münster, D-48149 Münster, Germany
| | - Denise Pajonczyk
- Institute-associated Research Group "Cell adhesion and cell polarity", ZMBE, University of Münster, D-48149 Münster, Germany.,Institute of Medical Biochemistry, ZMBE, University of Münster, D-48149 Münster, Germany
| | - Sophia Leußink
- Institute-associated Research Group "Cell adhesion and cell polarity", ZMBE, University of Münster, D-48149 Münster, Germany.,Institute of Medical Biochemistry, ZMBE, University of Münster, D-48149 Münster, Germany
| | - Frauke Brinkmann
- Institute-associated Research Group "Cell adhesion and cell polarity", ZMBE, University of Münster, D-48149 Münster, Germany.,Institute of Medical Biochemistry, ZMBE, University of Münster, D-48149 Münster, Germany
| | - Mark Glaesner-Ebnet
- Institute-associated Research Group "Cell adhesion and cell polarity", ZMBE, University of Münster, D-48149 Münster, Germany.,Institute of Medical Biochemistry, ZMBE, University of Münster, D-48149 Münster, Germany
| | - Eva Wardelmann
- Gerhard-Domagk-Institute of Pathology, University Hospital Münster, D-48149 Münster, Germany
| | - Thomas Zobel
- Imaging Network Microscopy, University of Münster, D-48149 Münster, Germany
| | - M Alexander Schmidt
- Institute of Infectiology, ZMBE, University of Münster, D-48149 Münster, Germany
| | | | - Volker Gerke
- Institute of Medical Biochemistry, ZMBE, University of Münster, D-48149 Münster, Germany.,Cells-in-Motion Interfaculty Center (CiMIC), University of Münster, D-48419 Münster, Germany
| | - Klaus Ebnet
- Institute-associated Research Group "Cell adhesion and cell polarity", ZMBE, University of Münster, D-48149 Münster, Germany.,Institute of Medical Biochemistry, ZMBE, University of Münster, D-48149 Münster, Germany.,Cells-in-Motion Interfaculty Center (CiMIC), University of Münster, D-48419 Münster, Germany.,Interdisciplinary Center for Clinical Research (IZKF), University of Münster, D-48149 Münster, Germany
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2
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Pushpakumar S, Ahmad A, Ketchem CJ, Jose PA, Weinman EJ, Sen U, Lederer ED, Khundmiri SJ. Sodium-hydrogen exchanger regulatory factor-1 (NHERF1) confers salt sensitivity in both male and female models of hypertension in aging. Life Sci 2020; 243:117226. [PMID: 31904366 PMCID: PMC7015806 DOI: 10.1016/j.lfs.2019.117226] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/16/2019] [Accepted: 12/23/2019] [Indexed: 01/11/2023]
Abstract
Hypertension is a risk factor for premature death and roughly 50% of hypertensive patients are salt-sensitive. The incidence of salt-sensitive hypertension increases with age. However, the mechanisms of salt-sensitive hypertension are not well understood. We had demonstrated decreased renal sodium‑hydrogen exchanger regulatory factor 1 (NHERF1) expression in old salt-resistant F344 rats. Based on those studies we hypothesized that NHERF1 expression is required for the development of some forms of salt-sensitive hypertension. To address this hypothesis, we measured blood pressure in NHERF1 expressing salt-sensitive 4-mo and 24-mo-old male and female Fischer Brown Norway (FBN) rats male and female 18-mo-old NHERF1 knock-out (NHERF1-/-) mice and wild-type (WT) littermates on C57BL/6J background after feeding high salt (8% NaCl) diet for 7 days. Our data demonstrate that 8% salt diet increased blood pressure in both male and female 24-mo-old FBN rats but not in 4-mo-old FBN rats and in 18-mo-old male and female WT mice but not in NHERF1-/- mice. Renal dopamine 1 receptor (D1R) expression was decreased in 24-mo-old rats, compared with 4-mo-old FBN rats. However, sodium chloride cotransporter (NCC) expression increased in 24-mo-old FBN rats. In FBN rats, age had no effect on NaK ATPase α1 and NKCC2 expression. By contrast, high salt diet increased the renal expressions of NKCC2, and NCC in 24-mo-old FBN rats. High salt diet also increased NKCC2 and NCC expression in WT mice but not NHERF1-/- mice. Our data suggest that renal NHERF1 expression confers salt sensitivity with aging, associated with increased expression of sodium transporters.
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Affiliation(s)
- Sathnur Pushpakumar
- Department of Physiology, University of Louisville, Louisville, KY, United States of America
| | - Asrar Ahmad
- Department of Physiology and Biophysics, Howard University College of Medicine, Washington, DC, United States of America
| | - Corey J Ketchem
- Department of Medicine, Nephrology and Hypertension, University of Louisville, Louisville, KY, United States of America
| | - Pedro A Jose
- Department of Medicine, Division of Renal Diseases and Hypertension, The George Washington University, Washington, DC, United States of America
| | - Edward J Weinman
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Utpal Sen
- Department of Physiology, University of Louisville, Louisville, KY, United States of America
| | - Eleanor D Lederer
- Department of Physiology, University of Louisville, Louisville, KY, United States of America; Department of Medicine, Nephrology and Hypertension, University of Louisville, Louisville, KY, United States of America; Robley Rex VA Medical Center, Louisville, KY, United States of America
| | - Syed J Khundmiri
- Department of Physiology and Biophysics, Howard University College of Medicine, Washington, DC, United States of America.
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What if? Mouse proteomics after gene inactivation. J Proteomics 2019; 199:102-122. [DOI: 10.1016/j.jprot.2019.03.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 03/09/2019] [Accepted: 03/10/2019] [Indexed: 12/17/2022]
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Avula LR, Chen T, Kovbasnjuk O, Donowitz M. Both NHERF3 and NHERF2 are necessary for multiple aspects of acute regulation of NHE3 by elevated Ca 2+, cGMP, and lysophosphatidic acid. Am J Physiol Gastrointest Liver Physiol 2018; 314:G81-G90. [PMID: 28882822 PMCID: PMC5866371 DOI: 10.1152/ajpgi.00140.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The intestinal epithelial brush border Na+/H+ exchanger NHE3 accounts for a large component of intestinal Na absorption. NHE3 is regulated during digestion by signaling complexes on its COOH terminus that include the four multi-PDZ domain-containing NHERF family proteins. All bind to NHE3 and take part in different aspects of NHE3 regulation. Because the roles of each NHERF appear to vary on the basis of the cell model or intestinal segment studied and because of our recent finding that a NHERF3-NHERF2 heterodimer appears important for NHE3 regulation in Caco-2 cells, we examined the role of NHERF3 and NHERF2 in C57BL/6 mouse jejunum using homozygous NHERF2 and NHERF3 knockout mice. NHE3 activity was determined with two-photon microscopy and the dual-emission pH-sensitive dye SNARF-4F. The jejunal apical membrane of NHERF3-null mice appeared similar to wild-type (WT) mice in surface area, microvillus number, and height, which is similar to results previously reported for jejunum of NHERF2-null mice. NHE3 basal activity was not different from WT in either NHERF2- or NHERF3-null jejunum, while d-glucose-stimulated NHE3 activity was reduced in NHERF2, but similar to WT in NHERF3 KO. LPA stimulation and UTP (elevated Ca2+) and cGMP inhibition of NHE3 were markedly reduced in both NHERF2- and NHERF3-null jejunum. Forskolin inhibited NHE3 in NHERF3-null jejunum, but the extent of inhibition was reduced compared with WT. The forskolin inhibition of NHE3 in NHERF2-null mice was too inconsistent to determine whether there was an effect and whether it was altered compared with the WT response. These results demonstrate similar requirement for NHERF2 and NHERF3 in mouse jejunal NHE3 regulation by LPA, Ca2+, and cGMP. The explanation for the similarity is not known but is consistent with involvement of a brush-border NHERF3-NHERF2 heterodimer or sequential NHERF-dependent effects in these aspects of NHE3 regulation. NEW & NOTEWORTHY NHERF2 and NHERF3 are apical membrane multi-PDZ domain-containing proteins that are involved in regulation of intestinal NHE3. This study demonstrates that NHERF2 and NHERF3 have overlapping roles in NHE3 stimulation by LPA and inhibition by elevated Ca2+ and cGMP. These results are consistent with their role being as a NHERF3-NHERF2 heterodimer or via sequential NHERF-dependent signaling steps, and they begin to clarify a role for multiple NHERF proteins in NHE3 regulation.
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Affiliation(s)
- Leela Rani Avula
- 1Department of Medicine, the Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Tiane Chen
- 1Department of Medicine, the Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Olga Kovbasnjuk
- 1Department of Medicine, the Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Mark Donowitz
- 1Department of Medicine, the Johns Hopkins School of Medicine, Baltimore, Maryland,2Department of Physiology, the Johns Hopkins University School of Medicine, Baltimore, Maryland
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Yoshida S, Fukutomi T, Kimura T, Sakurai H, Hatano R, Yamamoto H, Mukaisho KI, Hattori T, Sugihara H, Asano S. Comprehensive proteome analysis of brush border membrane fraction of ileum of ezrin knockdown mice. Biomed Res 2017; 37:127-39. [PMID: 27108882 DOI: 10.2220/biomedres.37.127] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Ezrin is an actin binding protein which cross-links membrane proteins with cytoskeleton directly or indirectly via PDZ domain-containing scaffold proteins. It is mainly expressed at the brush border membrane (BBM) of gastrointestinal tracts, and is involved in the construction of microvilli structure and the functional expression of membrane protein complexes at the cell surface. To precisely study the roles of ezrin on the expression of membrane proteins at the cell surface, here we prepared the BBM fractions of ileums from the wild-type and ezrin-knockdown (Vil2(kd/kd)) mice, analyzed them by mass spectrometry, and compared their proteomic patterns. Totally 313 proteins were identified in the BBM fractions. Several transport proteins, cytoskeleton-associated proteins, and trafficking proteins were up- or down-regulated in the BBM fraction of the ileum in the Vil2(kd/kd) mice. Among them, the expressions of i) Na(+)/H(+) exchanger regulatory factor 1 (a PDZ domain-containing scaffold protein), ii) sodium monocarboxylate transporter 1, which contains a PDZ domain-binding motif at their carboxy-terminal, and iii) chloride intracellular channel protein 5 were down-regulated at the BBM fraction of the ileum in the Vil2(kd/kd) mice, suggesting that ezrin is involved in their expression in the BBM.
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Affiliation(s)
- Saori Yoshida
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University
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Sauvanet C, Wayt J, Pelaseyed T, Bretscher A. Structure, Regulation, and Functional Diversity of Microvilli on the Apical Domain of Epithelial Cells. Annu Rev Cell Dev Biol 2015; 31:593-621. [DOI: 10.1146/annurev-cellbio-100814-125234] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Cécile Sauvanet
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
| | - Jessica Wayt
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
| | - Thaher Pelaseyed
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
| | - Anthony Bretscher
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
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Abstract
PURPOSE OF REVIEW In this review, we focus on the recent (March 2010 to September 2011) advances in small intestinal ion transport, with particular emphasis on sodium, chloride, bicarbonate, and calcium transport mechanisms under physiological and pathophysiological conditions. RECENT FINDINGS Knockout of NHERF1 and NHERF2 allowed translation of the data largely derived from the in-vitro models into a living organism. These studies also expand our knowledge about the complexity of intestinal transporter interactomes, define the role for scaffolding proteins in basal and regulated apical transport, and help identify potential targets for pharmacological approaches. We continue to accumulate novel information about the function and regulation of NHE3 (including its role in regulating paracellular Ca2+ flux), NHE8, as well as about the complexity of the intestinal Cl- and HCO3- transport in health and disease. SUMMARY Thanks to the new genetically engineered mouse models, a significant progress has been made in our understanding of the role of NHERF proteins in regulation of intestinal Na+ absorption. Significant novel data on the coordinated function of bicarbonate, chloride, and sodium transporters contributes to our current views of the integrative physiology of the small intestinal electrolyte transport.
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Hryciw DH, Jenkin KA, Simcocks AC, Grinfeld E, McAinch AJ, Poronnik P. The interaction between megalin and ClC-5 is scaffolded by the Na⁺-H⁺ exchanger regulatory factor 2 (NHERF2) in proximal tubule cells. Int J Biochem Cell Biol 2012; 44:815-23. [PMID: 22349218 DOI: 10.1016/j.biocel.2012.02.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 01/22/2012] [Accepted: 02/05/2012] [Indexed: 11/25/2022]
Abstract
Albumin endocytosis in the proximal tubule is mediated by a number of proteins, including the scavenger receptor megalin/cubilin and the PSD-95/Dlg/ZO-1 (PDZ) scaffolds NHERF1 and NHERF2. In addition, in a number of in vitro and in vivo models, the loss of ClC-5 results in a decreased cell surface expression and whole cell level of megalin, suggesting an interaction between these two proteins in vivo. We investigated if ClC-5 and megalin interact directly, and as ClC-5 binds to NHERF2, we investigated if this PDZ scaffold was required for a megalin/ClC-5 complex. GST-pulldown and immunoprecipitation experiments using rat kidney lysate demonstrated an interaction between ClC-5 and megalin, which was mediated by their C-termini. As this interaction may be controlled by a scaffold protein, we characterised any interaction between megalin and NHERF2. Immunoprecipitation experiments indicated that megalin interacts with NHERF2 in vivo, and that this interaction was via an internal NHERF binding domain in the C-terminus of megalin and PDZ2 and the C-terminus of NHERF2. Silencing NHERF2 had no effect on megalin protein levels in the whole cell or plasma membrane. Using siRNA against NHERF2, we demonstrated that NHERF2 was required to facilitate the interaction between megalin and ClC-5. Using fusion proteins, we characterised a protein complex containing ClC-5 and megalin, which is scaffolded by NHERF2, in the absence of any other proteins. Importantly, these observations are the first to describe an interaction between megalin and ClC-5, which is scaffolded by NHERF2 in proximal tubule cells.
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Affiliation(s)
- D H Hryciw
- Biomedical and Lifestyle Diseases Unit, School of Biomedical and Health Sciences, Victoria University, St Albans, VIC 3021, Australia.
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Ardura JA, Friedman PA. Regulation of G protein-coupled receptor function by Na+/H+ exchange regulatory factors. Pharmacol Rev 2011; 63:882-900. [PMID: 21873413 DOI: 10.1124/pr.110.004176] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Many G protein-coupled receptors (GPCR) exert patterns of cell-specific signaling and function. Mounting evidence now supports the view that cytoplasmic adapter proteins contribute critically to this behavior. Adapter proteins recognize highly conserved motifs such as those for Src homology 3 (SH3), phosphotyrosine-binding (PTB), and postsynaptic density 95/discs-large/zona occludens (PDZ) docking sequences in candidate GPCRs. Here we review the behavior of the Na+/H+ exchange regulatory factor (NHERF) family of PDZ adapter proteins on GPCR signalling, trafficking, and function. Structural determinants of NHERF proteins that allow them to recognize targeted GPCRs are considered. NHERF1 and NHERF2 are capable also of modifying the assembled complex of accessory proteins such as β-arrestins, which have been implicated in regulating GPCR signaling. In addition, NHERF1 and NHERF2 modulate GPCR signaling by altering the G protein to which the receptor binds or affect other regulatory proteins that affect GTPase activity, protein kinase A, phospholipase C, or modify downstream signaling events. Small molecules targeting the site of NHERF1-GPCR interaction are being developed and may become important and selective drug candidates.
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Affiliation(s)
- Juan A Ardura
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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