1
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Staruschenko A, Alexander RT, Caplan MJ, Ilatovskaya DV. Calcium signalling and transport in the kidney. Nat Rev Nephrol 2024; 20:541-555. [PMID: 38641658 DOI: 10.1038/s41581-024-00835-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2024] [Indexed: 04/21/2024]
Abstract
The kidney plays a pivotal role in regulating calcium levels within the body. Approximately 98% of the filtered calcium is reabsorbed in the nephron, and this process is tightly controlled to maintain calcium homeostasis, which is required to facilitate optimal bone mineralization, preserve serum calcium levels within a narrow range, and support intracellular signalling mechanisms. The maintenance of these functions is attributed to a delicate balance achieved by various calcium channels, transporters, and calcium-binding proteins in renal cells. Perturbation of this balance due to deficiency or dysfunction of calcium channels and calcium-binding proteins can lead to severe complications. For example, polycystic kidney disease is linked to aberrant calcium transport and signalling. Furthermore, dysregulation of calcium levels can promote the formation of kidney stones. This Review provides an updated description of the key aspects of calcium handling in the kidney, focusing on the function of various calcium channels and the physiological stimuli that control these channels or are communicated through them. A discussion of the role of calcium as an intracellular second messenger and the pathophysiology of renal calcium dysregulation, as well as a summary of gaps in knowledge and future prospects, are also included.
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Affiliation(s)
- Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA.
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, USA.
- James A. Haley Veterans Hospital, Tampa, FL, USA.
| | - R Todd Alexander
- Department of Paediatrics, University of Alberta, Edmonton, AB, Canada
- Women's and Children's Health Institute, Edmonton, AB, Canada
| | - Michael J Caplan
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Daria V Ilatovskaya
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
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2
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Ha K, Mundt-Machado N, Bisignano P, Pinedo A, Raleigh DR, Loeb G, Reiter JF, Cao E, Delling M. Cilia-enriched oxysterol 7β,27-DHC is required for polycystin ion channel activation. Nat Commun 2024; 15:6468. [PMID: 39085216 PMCID: PMC11291729 DOI: 10.1038/s41467-024-50318-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 06/28/2024] [Indexed: 08/02/2024] Open
Abstract
Polycystin-1 (PC-1) and PC-2 form a heteromeric ion channel complex that is abundantly expressed in primary cilia of renal epithelial cells. This complex functions as a non-selective cation channel, and mutations within the polycystin complex cause autosomal dominant polycystic kidney disease (ADPKD). The spatial and temporal regulation of the polycystin complex within the ciliary membrane remains poorly understood. Using both whole-cell and ciliary patch-clamp recordings, we identify a cilia-enriched oxysterol, 7β,27-dihydroxycholesterol (DHC), that serves as a necessary activator of the polycystin complex. We further identify an oxysterol-binding pocket within PC-2 and showed that mutations within this binding pocket disrupt 7β,27-DHC-dependent polycystin activation. Pharmacologic and genetic inhibition of oxysterol synthesis reduces channel activity in primary cilia. In summary, our findings reveal a regulator of the polycystin complex. This oxysterol-binding pocket in PC-2 may provide a specific target for potential ADPKD therapeutics.
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Affiliation(s)
- Kodaji Ha
- Department of Physiology, University of California San Francisco, San Francisco, CA, USA
| | - Nadine Mundt-Machado
- Department of Physiology, University of California San Francisco, San Francisco, CA, USA
| | - Paola Bisignano
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Aide Pinedo
- Department of Physiology, University of California San Francisco, San Francisco, CA, USA
| | - David R Raleigh
- Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA, USA
| | - Gabriel Loeb
- Department of Medicine, University of California, San Francisco, CA, USA
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Erhu Cao
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Markus Delling
- Department of Physiology, University of California San Francisco, San Francisco, CA, USA.
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3
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Staudner T, Geiges L, Khamseekaew J, Sure F, Korbmacher C, Ilyaskin AV. Disease-associated missense mutations in the pore loop of polycystin-2 alter its ion channel function in a heterologous expression system. J Biol Chem 2024; 300:107574. [PMID: 39009345 DOI: 10.1016/j.jbc.2024.107574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 06/20/2024] [Accepted: 07/03/2024] [Indexed: 07/17/2024] Open
Abstract
Polycystin-2 (PC2) is mutated in ∼15% of patients with autosomal dominant polycystic kidney disease (ADPKD). PC2 belongs to the family of transient receptor potential (TRP) channels and can function as a homotetramer. We investigated whether three disease-associated mutations (F629S, C632R, or R638C) localized in the channel's pore loop alter ion channel properties of human PC2 expressed in Xenopus laevis oocytes. Expression of wild-type (WT) PC2 typically resulted in small but measurable Na+ inward currents in the absence of extracellular divalent cations. These currents were no longer observed when individual pore mutations were introduced in WT PC2. Similarly, Na+ inward currents mediated by the F604P gain-of-function (GOF) PC2 construct (PC2 F604P) were abolished by each of the three pore mutations. In contrast, when the mutations were introduced in another GOF construct, PC2 L677A N681A, only C632R had a complete loss-of-function effect, whereas significant residual Na+ inward currents were observed with F629S (∼15%) and R638C (∼30%). Importantly, the R638C mutation also abolished the Ca2+ permeability of PC2 L677A N681A and altered its monovalent cation selectivity. To elucidate the molecular mechanisms by which the R638C mutation affects channel function, molecular dynamics (MD) simulations were used in combination with functional experiments and site-directed mutagenesis. Our findings suggest that R638C stabilizes ionic interactions between Na+ ions and the selectivity filter residue D643. This probably explains the reduced monovalent cation conductance of the mutant channel. In summary, our data support the concept that altered ion channel properties of PC2 contribute to the pathogenesis of ADPKD.
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Affiliation(s)
- Tobias Staudner
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Cellular and Molecular Physiology, Erlangen, Germany
| | - Linda Geiges
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Cellular and Molecular Physiology, Erlangen, Germany
| | - Juthamas Khamseekaew
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Cellular and Molecular Physiology, Erlangen, Germany
| | - Florian Sure
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Cellular and Molecular Physiology, Erlangen, Germany
| | - Christoph Korbmacher
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Cellular and Molecular Physiology, Erlangen, Germany
| | - Alexandr V Ilyaskin
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Cellular and Molecular Physiology, Erlangen, Germany.
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4
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Hilgendorf KI, Myers BR, Reiter JF. Emerging mechanistic understanding of cilia function in cellular signalling. Nat Rev Mol Cell Biol 2024; 25:555-573. [PMID: 38366037 PMCID: PMC11199107 DOI: 10.1038/s41580-023-00698-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2023] [Indexed: 02/18/2024]
Abstract
Primary cilia are solitary, immotile sensory organelles present on most cells in the body that participate broadly in human health, physiology and disease. Cilia generate a unique environment for signal transduction with tight control of protein, lipid and second messenger concentrations within a relatively small compartment, enabling reception, transmission and integration of biological information. In this Review, we discuss how cilia function as signalling hubs in cell-cell communication using three signalling pathways as examples: ciliary G-protein-coupled receptors (GPCRs), the Hedgehog (Hh) pathway and polycystin ion channels. We review how defects in these ciliary signalling pathways lead to a heterogeneous group of conditions known as 'ciliopathies', including metabolic syndromes, birth defects and polycystic kidney disease. Emerging understanding of these pathways' transduction mechanisms reveals common themes between these cilia-based signalling pathways that may apply to other pathways as well. These mechanistic insights reveal how cilia orchestrate normal and pathophysiological signalling outputs broadly throughout human biology.
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Affiliation(s)
- Keren I Hilgendorf
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA.
| | - Benjamin R Myers
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA.
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT, USA.
- Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT, USA.
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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5
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Fan Q, Hadla M, Peterson Z, Nelson G, Ye H, Wang X, Mardirossian JM, Harris PC, Alper SL, Prakash YS, Beyder A, Torres VE, Chebib FT. Activation of Piezo1 Inhibits Kidney Cystogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.11.593717. [PMID: 38766249 PMCID: PMC11101129 DOI: 10.1101/2024.05.11.593717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
The disruption of calcium signaling associated with polycystin deficiency has been proposed as the primary event underlying the increased abnormally patterned epithelial cell growth characteristic of Polycystic Kidney Disease. Calcium can be regulated through mechanotransduction, and the mechanosensitive cation channel Piezo1 has been implicated in sensing of intrarenal pressure and in urinary osmoregulation. However, a possible role for PIEZO1 in kidney cystogenesis remains undefined. We hypothesized that cystogenesis in ADPKD reflects altered mechanotransduction, suggesting activation of mechanosensitive cation channels as a therapeutic strategy for ADPKD. Here, we show that Yoda-1 activation of PIEZO1 increases intracellular Ca 2+ and reduces forskolin-induced cAMP levels in mIMCD3 cells. Yoda-1 reduced forskolin-induced IMCD cyst surface area in vitro and in mouse metanephros ex vivo in a dose-dependent manner. Knockout of polycystin-2 dampened the efficacy of PIEZO1 activation in reducing both cAMP levels and cyst surface area in IMCD3 cells. However, collecting duct-specific Piezo1 knockout neither induced cystogenesis in wild-type mice nor affected cystogenesis in the Pkd1 RC/RC model of ADPKD. Our study suggests that polycystin-2 and PIEZO1 play a role in mechanotransduction during cystogenesis in vitro , and ex vivo , but that in vivo cyst expansion may require inactivation or repression of additional suppressors of cystogenesis and/or growth. Our study provides a preliminary proof of concept for PIEZO1 activation as a possible component of combination chemotherapy to retard or halt cystogenesis and/or cyst growth.
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Mbiakop UC, Jaggar JH. Vascular polycystin proteins in health and disease. Microcirculation 2024; 31:e12834. [PMID: 37823335 PMCID: PMC11009377 DOI: 10.1111/micc.12834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/25/2023] [Accepted: 10/05/2023] [Indexed: 10/13/2023]
Abstract
PKD1 (polycystin 1) and PKD2 (polycystin 2) are expressed in a variety of different cell types, including arterial smooth muscle and endothelial cells. PKD1 is a transmembrane domain protein with a large extracellular N-terminus that is proposed to act as a mechanosensor and receptor. PKD2 is a member of the transient receptor potential (TRP) channel superfamily which is also termed TRPP1. Mutations in the genes which encode PKD1 and PKD2 lead to autosomal dominant polycystic kidney disease (ADPKD). ADPKD is one of the most prevalent monogenic disorders in humans and is associated with extrarenal and vascular complications, including hypertension. Recent studies have uncovered mechanisms of activation and physiological functions of PKD1 and PKD2 in arterial smooth muscle and endothelial cells. It has also been found that PKD function is altered in the vasculature during ADPKD and hypertension. We will summarize this work and discuss future possibilities for this area of research.
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Affiliation(s)
- Ulrich C. Mbiakop
- Department of Physiology, University of Tennessee Health Science Center, Memphis TN 38163
| | - Jonathan H. Jaggar
- Department of Physiology, University of Tennessee Health Science Center, Memphis TN 38163
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7
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Wang Z, Chen M, Su Q, Morais TDC, Wang Y, Nazginov E, Pillai AR, Qian F, Shi Y, Yu Y. Molecular and structural basis of the dual regulation of the polycystin-2 ion channel by small-molecule ligands. Proc Natl Acad Sci U S A 2024; 121:e2316230121. [PMID: 38483987 PMCID: PMC10962963 DOI: 10.1073/pnas.2316230121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 02/12/2024] [Indexed: 03/19/2024] Open
Abstract
Mutations in the PKD2 gene, which encodes the polycystin-2 (PC2, also called TRPP2) protein, lead to autosomal dominant polycystic kidney disease (ADPKD). As a member of the transient receptor potential (TRP) channel superfamily, PC2 functions as a non-selective cation channel. The activation and regulation of the PC2 channel are largely unknown, and direct binding of small-molecule ligands to this channel has not been reported. In this work, we found that most known small-molecule agonists of the mucolipin TRP (TRPML) channels inhibit the activity of the PC2_F604P, a gain-of-function mutant of the PC2 channel. However, two of them, ML-SA1 and SF-51, have dual regulatory effects, with low concentration further activating PC2_F604P, and high concentration leading to inactivation of the channel. With two cryo-electron microscopy (cryo-EM) structures, a molecular docking model, and mutagenesis results, we identified two distinct binding sites of ML-SA1 in PC2_F604P that are responsible for activation and inactivation, respectively. These results provide structural and functional insights into how ligands regulate PC2 channel function through unusual mechanisms and may help design compounds that are more efficient and specific in regulating the PC2 channel and potentially also for ADPKD treatment.
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Affiliation(s)
- Zhifei Wang
- Department of Biological Sciences, St. John’s University, Queens, NY11375
| | - Mengying Chen
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang province310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang province310024, China
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Qiang Su
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang province310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang province310024, China
| | - Tiago D. C. Morais
- Department of Biological Sciences, St. John’s University, Queens, NY11375
| | - Yan Wang
- Department of Biological Sciences, St. John’s University, Queens, NY11375
| | - Elianna Nazginov
- Department of Biological Sciences, St. John’s University, Queens, NY11375
| | - Akhilraj R. Pillai
- Department of Biological Sciences, St. John’s University, Queens, NY11375
| | - Feng Qian
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD21201
| | - Yigong Shi
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang province310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang province310024, China
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Yong Yu
- Department of Biological Sciences, St. John’s University, Queens, NY11375
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8
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Moran AL, Louzao-Martinez L, Norris DP, Peters DJM, Blacque OE. Transport and barrier mechanisms that regulate ciliary compartmentalization and ciliopathies. Nat Rev Nephrol 2024; 20:83-100. [PMID: 37872350 DOI: 10.1038/s41581-023-00773-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2023] [Indexed: 10/25/2023]
Abstract
Primary cilia act as cell surface antennae, coordinating cellular responses to sensory inputs and signalling molecules that regulate developmental and homeostatic pathways. Cilia are therefore critical to physiological processes, and defects in ciliary components are associated with a large group of inherited pleiotropic disorders - known collectively as ciliopathies - that have a broad spectrum of phenotypes and affect many or most tissues, including the kidney. A central feature of the cilium is its compartmentalized structure, which imparts its unique molecular composition and signalling environment despite its membrane and cytosol being contiguous with those of the cell. Such compartmentalization is achieved via active transport pathways that bring protein cargoes to and from the cilium, as well as gating pathways at the ciliary base that establish diffusion barriers to protein exchange into and out of the organelle. Many ciliopathy-linked proteins, including those involved in kidney development and homeostasis, are components of the compartmentalizing machinery. New insights into the major compartmentalizing pathways at the cilium, namely, ciliary gating, intraflagellar transport, lipidated protein flagellar transport and ciliary extracellular vesicle release pathways, have improved our understanding of the mechanisms that underpin ciliary disease and associated renal disorders.
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Affiliation(s)
- Ailis L Moran
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Laura Louzao-Martinez
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Dorien J M Peters
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.
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9
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Yasinoglu SA, Kuipers TB, Suidgeest E, van der Weerd L, Mei H, Baelde HJ, Peters DJM. Transcriptomic profiling of Polycystic Kidney Disease identifies paracrine factors in the early cyst microenvironment. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166987. [PMID: 38070582 DOI: 10.1016/j.bbadis.2023.166987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/30/2023] [Accepted: 12/04/2023] [Indexed: 12/21/2023]
Abstract
Initial cysts that are formed upon Pkd1 loss in mice impose persistent stress on surrounding tissue and trigger a cystic snowball effect, in which local aberrant PKD-related signaling increases the likelihood of new cyst formation, ultimately leading to accelerated disease progression. Although many pathways have been associated with PKD progression, the knowledge of early changes near initial cysts is limited. To perform an unbiased analysis of transcriptomic alterations in the cyst microenvironment, microdomains were collected from kidney sections of iKsp-Pkd1del mice with scattered Pkd1-deletion using Laser Capture Microdissection. These microdomains were defined as F4/80-low cystic, representing early alterations in the cyst microenvironment, F4/80-high cystic, with more advanced alterations, or non-cystic. RNA sequencing and differential gene expression analysis revealed 953 and 8088 dysregulated genes in the F4/80-low and F4/80-high cyst microenvironment, respectively, when compared to non-cystic microdomains. In the early cyst microenvironment, several injury-repair, growth, and tissue remodeling-related pathways were activated, accompanied by mild metabolic changes. In the more advanced F4/80-high microdomains, these pathways were potentiated and the metabolism was highly dysregulated. Upstream regulator analysis revealed a series of paracrine factors with increased activity in the early cyst microenvironment, including TNFSF12 and OSM. In line with the upstream regulator analysis, TWEAK and Oncostatin-M promoted cell proliferation and inflammatory gene expression in renal epithelial cells and fibroblasts in vitro. Collectively, our data provide an overview of molecular alterations that specifically occur in the cyst microenvironment and identify paracrine factors that may mediate early and advanced alterations in the cyst microenvironment.
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Affiliation(s)
- Sevtap A Yasinoglu
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Thomas B Kuipers
- Sequencing Analysis Support Core, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, the Netherlands
| | - Ernst Suidgeest
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Louise van der Weerd
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Hailiang Mei
- Sequencing Analysis Support Core, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, the Netherlands
| | - Hans J Baelde
- Department of Pathology, Leiden University Medical Center, Leiden, the Netherlands
| | - Dorien J M Peters
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands.
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10
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Bannell TAK, Cockburn JJB. The molecular structure and function of fibrocystin, the key gene product implicated in autosomal recessive polycystic kidney disease (ARPKD). Ann Hum Genet 2024; 88:58-75. [PMID: 37905714 DOI: 10.1111/ahg.12535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/14/2023] [Accepted: 10/03/2023] [Indexed: 11/02/2023]
Abstract
Autosomal recessive polycystic kidney disease is an early onset inherited hepatorenal disorder affecting around 1 in 20,000 births with no approved specific therapies. The disease is almost always caused by variations in the polycystic kidney and hepatic disease 1 gene, which encodes fibrocystin (FC), a very large, single-pass transmembrane glycoprotein found in primary cilia, urine and urinary exosomes. By comparison to proteins involved in autosomal dominant PKD, our structural and molecular understanding of FC has lagged far behind such that there are no published experimentally determined structures of any part of the protein. Bioinformatics analyses predict that the ectodomain contains a long chain of immunoglobulin-like plexin-transcription factor domains, a protective antigen 14 domain, a tandem G8-TMEM2 homology region and a sperm protein, enterokinase and agrin domain. Here we review current knowledge on the molecular function of the protein from a structural perspective.
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Affiliation(s)
- Travis A K Bannell
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Joseph J B Cockburn
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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11
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Kanhai AA, Sánchez-López E, Kuipers TB, van Klinken JB, Dijkstra KL, van der Veen I, Baelde HJ, Song X, Pei Y, Mei H, Leonhard WN, Mayboroda OA, Peters DJ. Short salsalate administration affects cell proliferation, metabolism, and inflammation in polycystic kidney disease. iScience 2023; 26:108278. [PMID: 38026227 PMCID: PMC10665819 DOI: 10.1016/j.isci.2023.108278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 09/04/2023] [Accepted: 10/17/2023] [Indexed: 12/01/2023] Open
Abstract
Metabolic reprogramming is a driver of autosomal dominant polycystic kidney disease (ADPKD) progression and a potential therapeutic intervention route. We showed before that the AMP-associated protein kinase (AMPK) activator salsalate attenuates cystic disease progression. Here, we aim to study the early, direct effects of short salsalate treatment in adult-onset conditional Pkd1 deletion mice. Cystic mice were treated with salsalate for two weeks, after which NMR metabolomics and RNA sequencing analyses were performed. Pkd1 deletion resulted in clear metabolomic dysregulation. Short salsalate treatment has small, but significant, effects, reverting acetylcarnitine and phosphocholine concentrations back to wildtype levels, and showing associations with altered purine metabolism. RNA sequencing revealed that short salsalate treatment, next to restoring energy metabolism toward wildtype levels, also affects cell proliferation and inflammation, in PKD. We show that salsalate positively affects major dysregulated processes in ADPKD: energy metabolism, cell proliferation, and inflammation, providing more insights into its working mechanisms.
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Affiliation(s)
- Anish A. Kanhai
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Elena Sánchez-López
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, the Netherlands
| | - Thomas B. Kuipers
- Sequencing Analysis Support Core, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, the Netherlands
| | - Jan B. van Klinken
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
- Laboratory Genetic Metabolic Diseases of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
- Core Facility Metabolomics, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Kyra L. Dijkstra
- Department of Pathology, Leiden University Medical Center, Leiden, the Netherlands
| | - Inge van der Veen
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Hans J. Baelde
- Department of Pathology, Leiden University Medical Center, Leiden, the Netherlands
| | - Xuewen Song
- Division of Nephrology, University Health Network and University of Toronto, Toronto, ON, Canada
| | - York Pei
- Division of Nephrology, University Health Network and University of Toronto, Toronto, ON, Canada
| | - Hailiang Mei
- Sequencing Analysis Support Core, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, the Netherlands
| | - Wouter N. Leonhard
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Oleg A. Mayboroda
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, the Netherlands
| | - Dorien J.M. Peters
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
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12
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Walker RV, Yao Q, Xu H, Maranto A, Swaney KF, Ramachandran S, Li R, Cassina L, Polster BM, Outeda P, Boletta A, Watnick T, Qian F. Fibrocystin/Polyductin releases a C-terminal fragment that translocates into mitochondria and suppresses cystogenesis. Nat Commun 2023; 14:6513. [PMID: 37845212 PMCID: PMC10579373 DOI: 10.1038/s41467-023-42196-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/03/2023] [Indexed: 10/18/2023] Open
Abstract
Fibrocystin/Polyductin (FPC), encoded by PKHD1, is associated with autosomal recessive polycystic kidney disease (ARPKD), yet its precise role in cystogenesis remains unclear. Here we show that FPC undergoes complex proteolytic processing in developing kidneys, generating three soluble C-terminal fragments (ICDs). Notably, ICD15, contains a novel mitochondrial targeting sequence at its N-terminus, facilitating its translocation into mitochondria. This enhances mitochondrial respiration in renal epithelial cells, partially restoring impaired mitochondrial function caused by FPC loss. FPC inactivation leads to abnormal ultrastructural morphology of mitochondria in kidney tubules without cyst formation. Moreover, FPC inactivation significantly exacerbates renal cystogenesis and triggers severe pancreatic cystogenesis in a Pkd1 mouse mutant Pkd1V/V in which cleavage of Pkd1-encoded Polycystin-1 at the GPCR Proteolysis Site is blocked. Deleting ICD15 enhances renal cystogenesis without inducing pancreatic cysts in Pkd1V/V mice. These findings reveal a direct link between FPC and a mitochondrial pathway through ICD15 cleavage, crucial for cystogenesis mechanisms.
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Affiliation(s)
- Rebecca V Walker
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Qin Yao
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Hangxue Xu
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Anthony Maranto
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kristen F Swaney
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sreekumar Ramachandran
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rong Li
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Mechanobiology Institute and Department of Biological Sciences, National University of Singapore, Singapore, 117411, Singapore
| | - Laura Cassina
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Patricia Outeda
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alessandra Boletta
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Terry Watnick
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Feng Qian
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
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13
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Clearman KR, Haycraft CJ, Croyle MJ, Collawn JF, Yoder BK. Functions of the primary cilium in the kidney and its connection with renal diseases. Curr Top Dev Biol 2023; 155:39-94. [PMID: 38043952 DOI: 10.1016/bs.ctdb.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The nonmotile primary cilium is a sensory structure found on most mammalian cell types that integrates multiple signaling pathways involved in tissue development and postnatal function. As such, mutations disrupting cilia activities cause a group of disorders referred to as ciliopathies. These disorders exhibit a wide spectrum of phenotypes impacting nearly every tissue. In the kidney, primary cilia dysfunction caused by mutations in polycystin 1 (Pkd1), polycystin 2 (Pkd2), or polycystic kidney and hepatic disease 1 (Pkhd1), result in polycystic kidney disease (PKD), a progressive disorder causing renal functional decline and end-stage renal disease. PKD affects nearly 1 in 1000 individuals and as there is no cure for PKD, patients frequently require dialysis or renal transplantation. Pkd1, Pkd2, and Pkhd1 encode membrane proteins that all localize in the cilium. Pkd1 and Pkd2 function as a nonselective cation channel complex while Pkhd1 protein function remains uncertain. Data indicate that the cilium may act as a mechanosensor to detect fluid movement through renal tubules. Other functions proposed for the cilium and PKD proteins in cyst development involve regulation of cell cycle and oriented division, regulation of renal inflammation and repair processes, maintenance of epithelial cell differentiation, and regulation of mitochondrial structure and metabolism. However, how loss of cilia or cilia function leads to cyst development remains elusive. Studies directed at understanding the roles of Pkd1, Pkd2, and Pkhd1 in the cilium and other locations within the cell will be important for developing therapeutic strategies to slow cyst progression.
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Affiliation(s)
- Kelsey R Clearman
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Courtney J Haycraft
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mandy J Croyle
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States.
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14
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Yamaguchi S, Kamino M, Hamamura M, Otsuguro KI. The cytosolic N-terminal region of heterologously-expressed transmembrane channel-like protein 1 (TMC1) can be cleaved in HEK293 cells. PLoS One 2023; 18:e0287249. [PMID: 37352201 PMCID: PMC10289374 DOI: 10.1371/journal.pone.0287249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/01/2023] [Indexed: 06/25/2023] Open
Abstract
Transmembrane channel-like protein 1 (TMC1) is a transmembrane protein forming mechano-electrical transduction (MET) channel, which transduces mechanical stimuli into electrical signals at the top of stereocilia of hair cells in the inner ear. As an unexpected phenomenon, we found that the cytosolic N-terminal (Nt) region of heterologously-expressed mouse TMC1 (mTMC1) was localized in nuclei of a small population of the transfected HEK293 cells. This raised the possibility that the Nt region of heterologously-expressed mTMC1 was cleaved and transported into the nucleus. To confirm the cleavage, we performed western blot analyses. The results revealed that at least a fragment of the Nt region was produced from heterologously-expressed mTMC1. Site-directed mutagenesis experiments identified amino acid residues which were required to produce the fragment. The accumulation of the heterologously-expressed Nt fragment into the nuclei depended on nuclear localization signals within the Nt region. Furthermore, a structural comparison showed a similarity between the Nt region of mTMC1 and basic region leucine zipper (bZIP) transcription factors. However, transcriptome analyses using a next-generation sequencer showed that the heterologously-expression of the Nt fragment of mTMC1 hardly altered expression levels of genes. Although it is still unknown what is the precise mechanism and the physiological significance of this cleavage, these results showed that the cytosolic Nt region of heterologously-expressed mTMC1 could be cleaved in HEK293 cells. Therefore, it should be taken into account that the cleavage of Nt region might influence the functional analysis of TMC1 by the heterologous-expression system using HEK293 cells.
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Affiliation(s)
- Soichiro Yamaguchi
- Laboratory of Physiology, Department of Basic Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Maho Kamino
- Laboratory of Pharmacology, Department of Basic Veterinary Sciences, School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Maho Hamamura
- Laboratory of Pharmacology, Department of Basic Veterinary Sciences, School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Ken-ichi Otsuguro
- Laboratory of Pharmacology, Department of Basic Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
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15
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Márquez-Nogueras KM, Vuchkovska V, Kuo IY. Calcium signaling in polycystic kidney disease- cell death and survival. Cell Calcium 2023; 112:102733. [PMID: 37023534 PMCID: PMC10348384 DOI: 10.1016/j.ceca.2023.102733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/20/2023] [Accepted: 03/30/2023] [Indexed: 04/03/2023]
Abstract
Polycystic kidney disease is typified by cysts in the kidney and extra-renal manifestations including hypertension and heart failure. The main genetic underpinning this disease are loss-of function mutations to the two polycystin proteins, polycystin 1 and polycystin 2. Molecularly, the disease is characterized by changes in multiple signaling pathways including down regulation of calcium signaling, which, in part, is contributed by the calcium permeant properties of polycystin 2. These signaling pathways enable the cystic cells to survive and avoid cell death. This review focuses on the studies that have emerged in the past 5 years describing how the structural insights gained from PC-1 and PC-2 inform the calcium dependent molecular pathways of autophagy and the unfolded protein response that are regulated by the polycystin proteins and how it leads to cell survival and/or cell death.
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Affiliation(s)
- Karla M Márquez-Nogueras
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, 2160 S. First Ave, Maywood, IL, USA
| | - Virdjinija Vuchkovska
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, 2160 S. First Ave, Maywood, IL, USA; Graduate School, Loyola University Chicago, 2160 S. First Ave, Maywood, IL, USA
| | - Ivana Y Kuo
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, 2160 S. First Ave, Maywood, IL, USA.
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16
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Wang Y, Wang Z, Pavel MA, Ng C, Kashyap P, Li B, Morais TDC, Ulloa GA, Yu Y. The diverse effects of pathogenic point mutations on ion channel activity of a gain-of-function polycystin-2. J Biol Chem 2023; 299:104674. [PMID: 37028763 PMCID: PMC10192930 DOI: 10.1016/j.jbc.2023.104674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 02/27/2023] [Accepted: 03/06/2023] [Indexed: 04/08/2023] Open
Abstract
Autosomal dominant polycystic kidney disease is caused by mutations in PKD1 or PKD2 genes. The latter encodes polycystin-2 (PC2, also known as TRPP2), a member of the transient receptor potential ion channel family. Despite most pathogenic mutations in PKD2 being truncation variants, there are also many point mutations, which cause small changes in protein sequences but dramatic changes in the in vivo function of PC2. How these mutations affect PC2 ion channel function is largely unknown. In this study, we systematically tested the effects of 31 point mutations on the ion channel activity of a gain-of-function PC2 mutant, PC2_F604P, expressed in Xenopus oocytes. The results show that all mutations in the transmembrane domains and channel pore region, and most mutations in the extracellular tetragonal opening for polycystins domain, are critical for PC2_F604P channel function. In contrast, the other mutations in the tetragonal opening for polycystins domain and most mutations in the C-terminal tail cause mild or no effects on channel function as assessed in Xenopus oocytes. To understand the mechanism of these effects, we have discussed possible conformational consequences of these mutations based on the cryo-EM structures of PC2. The results help gain insight into the structure and function of the PC2 ion channel and the molecular mechanism of pathogenesis caused by these mutations.
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Affiliation(s)
- Yan Wang
- Department of Biological Sciences, St. John's University, Queens, New York, USA
| | - Zhifei Wang
- Department of Biological Sciences, St. John's University, Queens, New York, USA
| | - Mahmud Arif Pavel
- Department of Biological Sciences, St. John's University, Queens, New York, USA
| | - Courtney Ng
- Department of Biological Sciences, St. John's University, Queens, New York, USA
| | - Parul Kashyap
- Department of Biological Sciences, St. John's University, Queens, New York, USA
| | - Bin Li
- Department of Biological Sciences, St. John's University, Queens, New York, USA
| | - Tiago D C Morais
- Department of Biological Sciences, St. John's University, Queens, New York, USA
| | - Gabriella A Ulloa
- Department of Biological Sciences, St. John's University, Queens, New York, USA
| | - Yong Yu
- Department of Biological Sciences, St. John's University, Queens, New York, USA.
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17
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Luo L, Roy S, Li L, Ma M. Polycystic kidney disease: novel insights into polycystin function. Trends Mol Med 2023; 29:268-281. [PMID: 36805211 DOI: 10.1016/j.molmed.2023.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 01/18/2023] [Accepted: 01/24/2023] [Indexed: 02/17/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a life-threatening monogenic disease caused by mutations in PKD1 and PKD2 that encode polycystin 1 (PC1) and polycystin 2 (PC2). PC1/2 localize to cilia of renal epithelial cells, and their function is believed to embody an inhibitory activity that suppresses the cilia-dependent cyst activation (CDCA) signal. Consequently, PC deficiency results in activation of CDCA and stimulates cyst growth. Recently, re-expression of PCs in established cysts has been shown to reverse PKD. Thus, the mode of action of PCs resembles a 'counterbalance in cruise control' to maintain lumen diameter within a designated range. Herein we review recent studies that point to novel arenas for future PC research with therapeutic potential for ADPKD.
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Affiliation(s)
- Lingfei Luo
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing, 400715, China
| | - Sudipto Roy
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Proteos, 61 Biopolis Drive, Singapore, 138673, Singapore; Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, Singapore, 119288, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
| | - Li Li
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing, 400715, China; Research Center of Stem cells and Ageing, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China
| | - Ming Ma
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing, 400715, China.
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18
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Liu X, Wang Y, Weng Z, Xu Q, Zhou C, Tang J, Chen XZ. Inhibition of TRPP3 by calmodulin through Ca 2+/calmodulin-dependent protein kinase II. CELL INSIGHT 2023; 2:100088. [PMID: 37193065 PMCID: PMC10134200 DOI: 10.1016/j.cellin.2023.100088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 05/18/2023]
Abstract
Transient receptor potential (TRP) polycystin-3 (TRPP3) is a non-selective cation channel activated by Ca2+ and protons and is involved in regulating ciliary Ca2+ concentration, hedgehog signaling and sour tasting. The TRPP3 channel function and regulation are still not well understood. Here we investigated regulation of TRPP3 by calmodulin (CaM) by means of electrophysiology and Xenopus oocytes as an expression model. We found that TRPP3 channel function is enhanced by calmidazolium, a CaM antagonist, and inhibited by CaM through binding of the CaM N-lobe to a TRPP3 C-terminal domain not overlapped with the EF-hand. We further revealed that the TRPP3/CaM interaction promotes phosphorylation of TRPP3 at threonine 591 by Ca2+/CaM-dependent protein kinase II, which mediates the inhibition of TRPP3 by CaM.
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Affiliation(s)
- Xiong Liu
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7, Edmonton, AB, Canada
| | - Yifang Wang
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7, Edmonton, AB, Canada
- National “111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, 430068, China
| | - Ziyi Weng
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7, Edmonton, AB, Canada
- National “111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, 430068, China
| | - Qinyi Xu
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7, Edmonton, AB, Canada
| | - Cefan Zhou
- National “111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, 430068, China
| | - JingFeng Tang
- National “111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, 430068, China
| | - Xing-Zhen Chen
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7, Edmonton, AB, Canada
- National “111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, 430068, China
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19
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Abstract
Polycystin subunits can form hetero- and homotetrameric ion channels in the membranes of various compartments of the cell. Homotetrameric polycystin channels are voltage- and calcium-modulated, whereas heterotetrameric versions are proposed to be ligand- or autoproteolytically regulated. Their importance is underscored by variants associated with autosomal dominant polycystic kidney disease and by vital roles in fertilization and embryonic development. The diversity in polycystin assembly and subcellular distribution allows for a multitude of sensory functions by this class of channels. In this review, we highlight their recent structural and functional characterization, which has provided a molecular blueprint to investigate the conformational changes required for channel opening in response to unique stimuli. We consider each polycystin channel type individually, discussing how they contribute to sensory cell biology, as well as their impact on the physiology of various tissues.
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Affiliation(s)
- Orhi Esarte Palomero
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA;
| | - Megan Larmore
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA;
| | - Paul G DeCaen
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA;
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20
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Bissler JJ, Batchelor D, Kingswood JC. Progress in Tuberous Sclerosis Complex Renal Disease. Crit Rev Oncog 2023; 27:35-49. [PMID: 36734871 DOI: 10.1615/critrevoncog.2022042857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects both fetal development and postnatal tissue growth, resulting in altered brain structures and a tumor predisposition syndrome. Although every organ system is affected by the disease, kidney involvement is a leading cause of death in adults with TSC. Over the past decade, significant progress has been made in understanding the renal disease. This review focuses on the cystic and solid renal lesions in TSC, including their pathobiology and treatment.
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Affiliation(s)
- John J Bissler
- Department of Pediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN 38105; Children's Foundation Research Institute (CFRI), Le Bonheur Children's Hospital, Memphis, TN 38105; Pediatric Medicine Department, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Dinah Batchelor
- Johns Hopkins All Children's Hospital, St. Petersburg, FL 33702
| | - J Christopher Kingswood
- Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Centre, St. Georges University of London, London, United Kingdom
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21
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Liu X, Zhang R, Fatehi M, Wang Y, Long W, Tian R, Deng X, Weng Z, Xu Q, Light PE, Tang J, Chen XZ. Regulation of PKD2 channel function by TACAN. J Physiol 2023; 601:83-98. [PMID: 36420836 DOI: 10.1113/jp283895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 11/18/2022] [Indexed: 11/26/2022] Open
Abstract
Autosomal dominant polycystic kidney disease is caused by mutations in the membrane receptor PKD1 or the cation channel PKD2. TACAN (also termed TMEM120A), recently reported as an ion channel in neurons for mechanosensing and pain sensing, is also distributed in diverse non-neuronal tissues, such as kidney, heart and intestine, suggesting its involvement in other functions. In this study, we found that TACAN is in a complex with PKD2 in native renal cell lines. Using the two-electrode voltage clamp in Xenopus oocytes, we found that TACAN inhibits the channel activity of PKD2 gain-of-function mutant F604P. TACAN fragments containing the first and last transmembrane domains interacted with the PKD2 C- and N-terminal fragments, respectively. The TACAN N-terminus acted as a blocking peptide, and TACAN inhibited the function of PKD2 by the binding of PKD2 with TACAN. By patch clamping in mammalian cells, we found that TACAN inhibits both the single-channel conductance and the open probability of PKD2 and mutant F604P. PKD2 co-expressed with TACAN, but not PKD2 alone, exhibited pressure sensitivity. Furthermore, we found that TACAN aggravates PKD2-dependent tail curvature and pronephric cysts in larval zebrafish. In summary, this study revealed that TACAN acts as a PKD2 inhibitor and mediates mechanosensitivity of the PKD2-TACAN channel complex. KEY POINTS: TACAN inhibits the function of PKD2 in vitro and in vivo. TACAN N-terminal S1-containing fragment T160X interacts with the PKD2 C-terminal fragment N580-L700, and its C-terminal S6-containing fragment L296-D343 interacts with the PKD2 N-terminal A594X. TACAN inhibits the function of the PKD2 channel by physical interaction. The complex of PKD2 with TACAN, but not PKD2 alone, confers mechanosensitivity.
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Affiliation(s)
- Xiong Liu
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Rui Zhang
- National '111' Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, China
| | - Mohammad Fatehi
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Yifang Wang
- National '111' Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, China
| | - Wentong Long
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Rui Tian
- National '111' Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, China
| | - Xiaoling Deng
- National '111' Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, China
| | - Ziyi Weng
- National '111' Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, China
| | - Qinyi Xu
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Peter E Light
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jingfeng Tang
- National '111' Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, China
| | - Xing-Zhen Chen
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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22
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Poddar A, Hsu YY, Zhang F, Shamma A, Kreais Z, Muller C, Malla M, Ray A, Liu AP, Chen Q. Membrane stretching activates calcium permeability of a putative channel Pkd2 during fission yeast cytokinesis. Mol Biol Cell 2022; 33:ar134. [PMID: 36200871 PMCID: PMC9727806 DOI: 10.1091/mbc.e22-07-0248] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Pkd2 is the fission yeast homologue of polycystins. This putative ion channel localizes to the plasma membrane. It is required for the expansion of cell volume during interphase growth and cytokinesis, the last step of cell division. However, the channel activity of Pkd2 remains untested. Here, we examined the calcium permeability and mechanosensitivity of Pkd2 through in vitro reconstitution and calcium imaging of pkd2 mutant cells. Pkd2 was translated and inserted into the lipid bilayers of giant unilamellar vesicles using a cell-free expression system. The reconstituted Pkd2 permeated calcium when the membrane was stretched via hypoosmotic shock. In vivo, inactivation of Pkd2 through a temperature-sensitive mutation pkd2-B42 reduced the average intracellular calcium level by 34%. Compared with the wild type, the hypomorphic mutation pkd2-81KD reduced the amplitude of hypoosmotic shock-triggered calcium spikes by 59%. During cytokinesis, mutations of pkd2 reduced the calcium spikes, accompanying cell separation and the ensuing membrane stretching, by 60%. We concluded that fission yeast polycystin Pkd2 allows calcium influx when activated by membrane stretching, representing a likely mechanosensitive channel that contributes to the cytokinetic calcium spikes.
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Affiliation(s)
- Abhishek Poddar
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Yen-Yu Hsu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109
| | - Faith Zhang
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Abeda Shamma
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606
| | - Zachary Kreais
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606
| | - Clare Muller
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Mamata Malla
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Aniruddha Ray
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606
| | - Allen P. Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109,Department of Biophysics, University of Michigan, Ann Arbor, MI 48109,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109,*Address correspondence to: Qian Chen (); Allen Liu ()
| | - Qian Chen
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606,*Address correspondence to: Qian Chen (); Allen Liu ()
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23
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Maser RL, Calvet JP, Parnell SC. The GPCR properties of polycystin-1- A new paradigm. Front Mol Biosci 2022; 9:1035507. [PMID: 36406261 PMCID: PMC9672506 DOI: 10.3389/fmolb.2022.1035507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022] Open
Abstract
Polycystin-1 (PC1) is an 11-transmembrane (TM) domain-containing protein encoded by the PKD1 gene, the most frequently mutated gene leading to autosomal dominant polycystic kidney disease (ADPKD). This large (> 462 kDal) protein has a complex posttranslational maturation process, with over five proteolytic cleavages having been described, and is found at multiple cellular locations. The initial description of the binding and activation of heterotrimeric Gαi/o by the juxtamembrane region of the PC1 cytosolic C-terminal tail (C-tail) more than 20 years ago opened the door to investigations, and controversies, into PC1's potential function as a novel G protein-coupled receptor (GPCR). Subsequent biochemical and cellular-based assays supported an ability of the PC1 C-tail to bind numerous members of the Gα protein family and to either inhibit or activate G protein-dependent pathways involved in the regulation of ion channel activity, transcription factor activation, and apoptosis. More recent work has demonstrated an essential role for PC1-mediated G protein regulation in preventing kidney cyst development; however, the mechanisms by which PC1 regulates G protein activity continue to be discovered. Similarities between PC1 and the adhesion class of 7-TM GPCRs, most notably a conserved GPCR proteolysis site (GPS) before the first TM domain, which undergoes autocatalyzed proteolytic cleavage, suggest potential mechanisms for PC1-mediated regulation of G protein signaling. This article reviews the evidence supporting GPCR-like functions of PC1 and their relevance to cystic disease, discusses the involvement of GPS cleavage and potential ligands in regulating PC1 GPCR function, and explores potential connections between PC1 GPCR-like activity and regulation of the channel properties of the polycystin receptor-channel complex.
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Affiliation(s)
- Robin L. Maser
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, United States
- Department of Clinical Laboratory Sciences, University of Kansas Medical Center, Kansas City, KS, United States
- Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - James P. Calvet
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, United States
- Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Stephen C. Parnell
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, United States
- Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
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24
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Scarinci N, Perez PL, Cantiello HF, Cantero MDR. Polycystin-2 (TRPP2) regulates primary cilium length in LLC-PK1 renal epithelial cells. Front Physiol 2022; 13:995473. [PMID: 36267587 PMCID: PMC9577394 DOI: 10.3389/fphys.2022.995473] [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: 07/15/2022] [Accepted: 09/14/2022] [Indexed: 11/21/2022] Open
Abstract
Polycystin-2 (PC2, TRPP2) is a Ca2+ permeable nonselective cation channel whose dysfunction generates autosomal dominant polycystic kidney disease (ADPKD). PC2 is present in different cell locations, including the primary cilium of renal epithelial cells. However, little is known as to whether PC2 contributes to the primary cilium structure. Here, we explored the effect(s) of external Ca2+, PC2 channel blockers, and PKD2 gene silencing on the length of primary cilia in wild-type LLC-PK1 renal epithelial cells. Confluent cell monolayers were fixed and immuno-labeled with an anti-acetylated α-tubulin antibody to identify primary cilia and measure their length. Although primary cilia length measurements did not follow a Normal distribution, the data were normalized by Box-Cox transformation rendering statistical differences under all experimental conditions. Cells exposed to high external Ca2+ (6.2 mM) decreased a 13.5% (p < 0.001) primary cilia length as compared to controls (1.2 mM Ca2+). In contrast, the PC2 inhibitors amiloride (200 μM) and LiCl (10 mM), both increased primary ciliary length by 33.2% (p < 0.001), and 17.4% (p < 0.001), respectively. PKD2 gene silencing by siRNA elicited a statistically significant, 10.3% (p < 0.001) increase in primary cilia length compared to their respective scrambled RNA transfected cells. The data indicate that conditions that regulate PC2 function or gene expression modify the length of primary cilia in renal epithelial cells. Blocking of PC2 mitigates the effects of elevated external Ca2+ concentration on primary cilia length. Proper regulation of PC2 function in the primary cilium may be essential in the onset of mechanisms that trigger cyst formation in ADPKD.
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25
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Liu X, Tang J, Chen XZ. Role of PKD2 in the endoplasmic reticulum calcium homeostasis. Front Physiol 2022; 13:962571. [PMID: 36035467 PMCID: PMC9399649 DOI: 10.3389/fphys.2022.962571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/15/2022] [Indexed: 11/25/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in the PKD1 or PKD2 gene which encodes membrane receptor PKD1 and cation channel PKD2, respectively. PKD2, also called transient receptor potential polycystin-2 (TRPP2), is a Ca2+-permeable channel located on the membrane of cell surface, primary cilia, and endoplasmic reticulum (ER). Ca2+ is closely associated with diverse cellular functions. While ER Ca2+ homeostasis depends on different Ca2+ receptors, channels and transporters, the role of PKD2 within the ER remains controversial. Whether and how PKD2-mediated ER Ca2+ leak relates to ADPKD pathogenesis is not well understood. Here, we reviewed current knowledge about the biophysical and physiological properties of PKD2 and how PKD2 contributes to ER Ca2+ homeostasis.
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Affiliation(s)
- Xiong Liu
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Jingfeng Tang
- National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, HB, China
| | - Xing-Zhen Chen
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
- *Correspondence: Xing-Zhen Chen,
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26
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Agborbesong E, Li LX, Li L, Li X. Molecular Mechanisms of Epigenetic Regulation, Inflammation, and Cell Death in ADPKD. Front Mol Biosci 2022; 9:922428. [PMID: 35847973 PMCID: PMC9277309 DOI: 10.3389/fmolb.2022.922428] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 06/07/2022] [Indexed: 11/13/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder, which is caused by mutations in the PKD1 and PKD2 genes, characterizing by progressive growth of multiple cysts in the kidneys, eventually leading to end-stage kidney disease (ESKD) and requiring renal replacement therapy. In addition, studies indicate that disease progression is as a result of a combination of factors. Understanding the molecular mechanisms, therefore, should facilitate the development of precise therapeutic strategies for ADPKD treatment. The roles of epigenetic modulation, interstitial inflammation, and regulated cell death have recently become the focuses in ADPKD. Different epigenetic regulators, and the presence of inflammatory markers detectable even before cyst growth, have been linked to cyst progression. Moreover, the infiltration of inflammatory cells, such as macrophages and T cells, have been associated with cyst growth and deteriorating renal function in humans and PKD animal models. There is evidence supporting a direct role of the PKD gene mutations to the regulation of epigenetic mechanisms and inflammatory response in ADPKD. In addition, the role of regulated cell death, including apoptosis, autophagy and ferroptosis, have been investigated in ADPKD. However, there is no consensus whether cell death promotes or delays cyst growth in ADPKD. It is therefore necessary to develop an interactive picture between PKD gene mutations, the epigenome, inflammation, and cell death to understand why inherited PKD gene mutations in patients may result in the dysregulation of these processes that increase the progression of renal cyst formation.
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Affiliation(s)
- Ewud Agborbesong
- Department of Internal Medicine, Mayo Clinic, Rochester, MN, United States.,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States
| | - Linda Xiaoyan Li
- Department of Internal Medicine, Mayo Clinic, Rochester, MN, United States.,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States
| | - Lu Li
- Department of Internal Medicine, Mayo Clinic, Rochester, MN, United States.,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States
| | - Xiaogang Li
- Department of Internal Medicine, Mayo Clinic, Rochester, MN, United States.,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States
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27
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Riddle HAL, Zhang S, Qian F, Williams JC, Stubbs JR, Rowe PSN, Parnell SC. Kidney stone formation in a novel murine model of polycystic kidney disease. Am J Physiol Renal Physiol 2022; 323:F59-F68. [PMID: 35343849 PMCID: PMC9236864 DOI: 10.1152/ajprenal.00165.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 03/16/2022] [Accepted: 03/16/2022] [Indexed: 11/22/2022] Open
Abstract
Individuals with autosomal dominant polycystic kidney disease have a higher incidence of stone formation than the general population. However, there are no cystic animal models known to develop stones. Cystic mice compound heterozygous for hypomorphic Pkd1V and Pkd1RC alleles develop cystic kidneys within a few weeks of birth but live beyond 20 wk of age, allowing for the study of cystic comorbidities including stone formation. Cystic Pkd1V/RC mice were euthanized at 3, 13, or 26 wk of age, and their kidneys were analyzed by microcomputed tomography (µCT) for stone formation. Mice had occasional mineral aggregates that could be detected by µCT analysis at 3 wk of age. At 13 or 26 wk of age, numerous white masses were visible beneath the kidney surface. µCT analysis confirmed the masses to be large mineral stone deposits throughout the renal cortex, with mineral content increasing with age. Staining of histological sections with alizarin red and von Kossa suggested that the stone deposits were composed primarily of calcium and phosphate. Microdissection confirmed stones localized within cyst lumens. Analysis of individual stones by µCT and infrared spectroscopy confirmed apatite mineral composition. Urinalysis revealed elevated levels of phosphate and citrate at 3 wk of age and lower pH and elevated levels of calcium and citrate at 13 wk of age, suggesting altered phosphate and calcium homeostasis as a potential cause of mineralization and renal stone formation. This is the first animal model exhibiting overt kidney stone formation in the context of cystic kidney disease.NEW & NOTEWORTHY Compound heterozygous Pkd1V/RC mice were found to form calcium phosphate-containing stones within cysts of the renal cortex by 13 wk of age. This is the first polycystic kidney disease animal model exhibiting spontaneous stone formation. A growing body of evidence suggests a link between renal stone formation and cystic kidney disease. This mouse model may be useful for studying the interplay between stone and cyst formation and the functional role of polycystins in mineral homeostasis.
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Affiliation(s)
- Heather A L Riddle
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
| | - Shiqin Zhang
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
| | - Feng Qian
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - James C Williams
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jason R Stubbs
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Peter Stanley N Rowe
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Stephen C Parnell
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas
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28
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Walker RV, Maranto A, Palicharla VR, Hwang SH, Mukhopadhyay S, Qian F. Cilia-Localized Counterregulatory Signals as Drivers of Renal Cystogenesis. Front Mol Biosci 2022; 9:936070. [PMID: 35832738 PMCID: PMC9272769 DOI: 10.3389/fmolb.2022.936070] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 05/30/2022] [Indexed: 12/18/2022] Open
Abstract
Primary cilia play counterregulatory roles in cystogenesis—they inhibit cyst formation in the normal renal tubule but promote cyst growth when the function of polycystins is impaired. Key upstream cilia-specific signals and components involved in driving cystogenesis have remained elusive. Recent studies of the tubby family protein, Tubby-like protein 3 (TULP3), have provided new insights into the cilia-localized mechanisms that determine cyst growth. TULP3 is a key adapter of the intraflagellar transport complex A (IFT-A) in the trafficking of multiple proteins specifically into the ciliary membrane. Loss of TULP3 results in the selective exclusion of its cargoes from cilia without affecting their extraciliary pools and without disrupting cilia or IFT-A complex integrity. Epistasis analyses have indicated that TULP3 inhibits cystogenesis independently of the polycystins during kidney development but promotes cystogenesis in adults when polycystins are lacking. In this review, we discuss the current model of the cilia-dependent cyst activation (CDCA) mechanism in autosomal dominant polycystic kidney disease (ADPKD) and consider the possible roles of ciliary and extraciliary polycystins in regulating CDCA. We then describe the limitations of this model in not fully accounting for how cilia single knockouts cause significant cystic changes either in the presence or absence of polycystins. Based on available data from TULP3/IFT-A-mediated differential regulation of cystogenesis in kidneys with deletion of polycystins either during development or in adulthood, we hypothesize the existence of cilia-localized components of CDCA (cCDCA) and cilia-localized cyst inhibition (CLCI) signals. We develop the criteria for cCDCA/CLCI signals and discuss potential TULP3 cargoes as possible cilia-localized components that determine cystogenesis in kidneys during development and in adult mice.
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Affiliation(s)
- Rebecca V. Walker
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Anthony Maranto
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| | | | - Sun-Hee Hwang
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Saikat Mukhopadhyay
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Feng Qian
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
- *Correspondence: Feng Qian,
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29
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Cantero MDR, Cantiello HF. Polycystin-2 (TRPP2): Ion channel properties and regulation. Gene 2022; 827:146313. [PMID: 35314260 DOI: 10.1016/j.gene.2022.146313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/19/2022] [Accepted: 02/08/2022] [Indexed: 12/01/2022]
Abstract
Polycystin-2 (TRPP2, PKD2, PC2) is the product of the PKD2 gene, whose mutations cause Autosomal Dominant Polycystic Kidney Disease (ADPKD). PC2 belongs to the superfamily of TRP (Transient Receptor Potential) proteins that generally function as Ca2+-permeable nonselective cation channels implicated in Ca2+ signaling. PC2 localizes to various cell domains with distinct functions that likely depend on interactions with specific channel partners. Functions include receptor-operated, nonselective cation channel activity in the plasma membrane, intracellular Ca2+ release channel activity in the endoplasmic reticulum (ER), and mechanosensitive channel activity in the primary cilium of renal epithelial cells. Here we summarize our current understanding of the properties of PC2 and how other transmembrane and cytosolic proteins modulate this activity, providing functional diversity and selective regulatory mechanisms to its role in the control of cellular Ca2+ homeostasis.
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Affiliation(s)
- María Del Rocío Cantero
- Laboratorio de Canales Iónicos, Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD, CONICET-UNSE), El Zanjón, Santiago del Estero 4206, Argentina.
| | - Horacio F Cantiello
- Laboratorio de Canales Iónicos, Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD, CONICET-UNSE), El Zanjón, Santiago del Estero 4206, Argentina
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30
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Ye Y, Lui VCH, Tam PKH. Pathogenesis of Choledochal Cyst: Insights from Genomics and Transcriptomics. Genes (Basel) 2022; 13:genes13061030. [PMID: 35741793 PMCID: PMC9223186 DOI: 10.3390/genes13061030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/07/2022] [Accepted: 06/07/2022] [Indexed: 12/10/2022] Open
Abstract
Choledochal cysts (CC) is characterized by extra- and/or intra-hepatic b\ile duct dilations. There are two main theories, “pancreaticobiliary maljunction” and “congenital stenosis of bile ducts” proposed for the pathogenesis of CC. Although family cases or CC associated with other anomalies have been reported, the molecular pathogenesis of CC is still poorly understood. Recent advances in transcriptomics and genomics analysis platforms have unveiled key expression signatures/genes/signaling pathways in the pathogenesis of human diseases including CC. This review summarizes insights from genomics and transcriptomics studies into the pathogenesis of CC, with the aim to improve (i) our understanding of its underlying complex pathomechanisms, and (ii) clinical management of different subtypes of CC, in particular their associated hepatic fibrotic change and their risk of malignancy transformation.
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Affiliation(s)
- Yongqin Ye
- Faculty of Medicine, Macau University of Science and Technology, Macau, China;
- Department of Surgery, School of Clinical Medicine, University of Hong Kong, Hong Kong, China;
| | - Vincent Chi Hang Lui
- Department of Surgery, School of Clinical Medicine, University of Hong Kong, Hong Kong, China;
| | - Paul Kwong Hang Tam
- Faculty of Medicine, Macau University of Science and Technology, Macau, China;
- Correspondence:
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31
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Abstract
Mutations of polycystin-1 (PC1) are the major cause (85% of cases) of autosomal dominant polycystic kidney disease (ADPKD), which is the fourth leading cause of kidney failure. PC1 is thought to function as an atypical G protein-coupled receptor, yet the mechanism by which PC1 regulates G-protein signaling remains poorly understood. A significant portion of ADPKD mutations of PC1 encode a protein with defects in maturation or reduced function that may be amenable to functional rescue. In this work, we have combined complementary biochemical and cellular assay experiments and accelerated molecular simulations, which revealed an allosteric transduction pathway in activation of the PC1 C-terminal fragment. Our findings will facilitate future rational drug design efforts targeting the PC1 signaling function. Polycystin-1 (PC1) is an important unusual G protein-coupled receptor (GPCR) with 11 transmembrane domains, and its mutations account for 85% of cases of autosomal dominant polycystic kidney disease (ADPKD). PC1 shares multiple characteristics with Adhesion GPCRs. These include a GPCR proteolysis site that autocatalytically divides these proteins into extracellular, N-terminal, and membrane-embedded, C-terminal fragments (CTF), and a tethered agonist (TA) within the N-terminal stalk of the CTF that is suggested to activate signaling. However, the mechanism by which a TA can activate PC1 is not known. Here, we have combined functional cellular signaling experiments of PC1 CTF expression constructs encoding wild type, stalkless, and three different ADPKD stalk variants with all-atom Gaussian accelerated molecular dynamics (GaMD) simulations to investigate TA-mediated signaling activation. Correlations of residue motions and free-energy profiles calculated from the GaMD simulations correlated with the differential signaling abilities of wild type and stalk variants of PC1 CTF. They suggested an allosteric mechanism involving residue interactions connecting the stalk, Tetragonal Opening for Polycystins (TOP) domain, and putative pore loop in TA-mediated activation of PC1 CTF. Key interacting residues such as N3074–S3585 and R3848–E4078 predicted from the GaMD simulations were validated by mutagenesis experiments. Together, these complementary analyses have provided insights into a TA-mediated activation mechanism of PC1 CTF signaling, which will be important for future rational drug design targeting PC1.
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32
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MacKay CE, Floen M, Leo MD, Hasan R, Garrud TAC, Fernández-Peña C, Singh P, Malik KU, Jaggar JH. A plasma membrane-localized polycystin-1/polycystin-2 complex in endothelial cells elicits vasodilation. eLife 2022; 11:e74765. [PMID: 35229718 PMCID: PMC8933003 DOI: 10.7554/elife.74765] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/25/2022] [Indexed: 11/25/2022] Open
Abstract
Polycystin-1 (PC-1, PKD1), a receptor-like protein expressed by the Pkd1 gene, is present in a wide variety of cell types, but its cellular location, signaling mechanisms, and physiological functions are poorly understood. Here, by studying tamoxifen-inducible, endothelial cell (EC)-specific Pkd1 knockout (Pkd1 ecKO) mice, we show that flow activates PC-1-mediated, Ca2+-dependent cation currents in ECs. EC-specific PC-1 knockout attenuates flow-mediated arterial hyperpolarization and vasodilation. PC-1-dependent vasodilation occurs over the entire functional shear stress range and via the activation of endothelial nitric oxide synthase (eNOS) and intermediate (IK)- and small (SK)-conductance Ca2+-activated K+ channels. EC-specific PC-1 knockout increases systemic blood pressure without altering kidney anatomy. PC-1 coimmunoprecipitates with polycystin-2 (PC-2, PKD2), a TRP polycystin channel, and clusters of both proteins locate in nanoscale proximity in the EC plasma membrane. Knockout of either PC-1 or PC-2 (Pkd2 ecKO mice) abolishes surface clusters of both PC-1 and PC-2 in ECs. Single knockout of PC-1 or PC-2 or double knockout of PC-1 and PC-2 (Pkd1/Pkd2 ecKO mice) similarly attenuates flow-mediated vasodilation. Flow stimulates nonselective cation currents in ECs that are similarly inhibited by either PC-1 or PC-2 knockout or by interference peptides corresponding to the C-terminus coiled-coil domains present in PC-1 or PC-2. In summary, we show that PC-1 regulates arterial contractility through the formation of an interdependent signaling complex with PC-2 in ECs. Flow stimulates PC-1/PC-2 clusters in the EC plasma membrane, leading to eNOS, IK channel, and SK channel activation, vasodilation, and a reduction in blood pressure.
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Affiliation(s)
- Charles E MacKay
- Department of Physiology, University of Tennessee Health Science CenterMemphisUnited States
| | - Miranda Floen
- Department of Physiology, University of Tennessee Health Science CenterMemphisUnited States
| | - M Dennis Leo
- Department of Physiology, University of Tennessee Health Science CenterMemphisUnited States
| | - Raquibul Hasan
- Department of Physiology, University of Tennessee Health Science CenterMemphisUnited States
| | - Tessa AC Garrud
- Department of Physiology, University of Tennessee Health Science CenterMemphisUnited States
| | - Carlos Fernández-Peña
- Department of Physiology, University of Tennessee Health Science CenterMemphisUnited States
| | - Purnima Singh
- Department of Physiology, University of Tennessee Health Science CenterMemphisUnited States
| | - Kafait U Malik
- Department of Physiology, University of Tennessee Health Science CenterMemphisUnited States
| | - Jonathan H Jaggar
- Department of Physiology, University of Tennessee Health Science CenterMemphisUnited States
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Lin HH, Ng KF, Chen TC, Tseng WY. Ligands and Beyond: Mechanosensitive Adhesion GPCRs. Pharmaceuticals (Basel) 2022; 15:ph15020219. [PMID: 35215331 PMCID: PMC8878244 DOI: 10.3390/ph15020219] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/10/2022] [Accepted: 02/10/2022] [Indexed: 02/07/2023] Open
Abstract
Cells respond to diverse types of mechanical stimuli using a wide range of plasma membrane-associated mechanosensitive receptors to convert extracellular mechanical cues into intracellular signaling. G protein-coupled receptors (GPCRs) represent the largest cell surface protein superfamily that function as versatile sensors for a broad spectrum of bio/chemical messages. In recent years, accumulating evidence has shown that GPCRs can also engage in mechano-transduction. According to the GRAFS classification system of GPCRs, adhesion GPCRs (aGPCRs) constitute the second largest GPCR subfamily with a unique modular protein architecture and post-translational modification that are well adapted for mechanosensory functions. Here, we present a critical review of current evidence on mechanosensitive aGPCRs.
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Affiliation(s)
- Hsi-Hsien Lin
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Department of Anatomic Pathology, Chang Gung Memorial Hospital-Linkou, Taoyuan 33305, Taiwan; (K.-F.N.); (T.-C.C.)
- Division of Rheumatology, Allergy and Immunology, Chang Gung Memorial Hospital-Keelung, Keelung 20401, Taiwan
- Correspondence: (H.-H.L.); (W.-Y.T.)
| | - Kwai-Fong Ng
- Department of Anatomic Pathology, Chang Gung Memorial Hospital-Linkou, Taoyuan 33305, Taiwan; (K.-F.N.); (T.-C.C.)
| | - Tse-Ching Chen
- Department of Anatomic Pathology, Chang Gung Memorial Hospital-Linkou, Taoyuan 33305, Taiwan; (K.-F.N.); (T.-C.C.)
| | - Wen-Yi Tseng
- Division of Rheumatology, Allergy and Immunology, Chang Gung Memorial Hospital-Keelung, Keelung 20401, Taiwan
- Department of Medicine, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Correspondence: (H.-H.L.); (W.-Y.T.)
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Sudarikova A, Vasileva V, Sultanova R, Ilatovskaya D. Recent advances in understanding ion transport mechanisms in polycystic kidney disease. Clin Sci (Lond) 2021; 135:2521-2540. [PMID: 34751394 PMCID: PMC8589009 DOI: 10.1042/cs20210370] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 10/15/2021] [Accepted: 10/26/2021] [Indexed: 12/18/2022]
Abstract
This review focuses on the most recent advances in the understanding of the electrolyte transport-related mechanisms important for the development of severe inherited renal disorders, autosomal dominant (AD) and recessive (AR) forms of polycystic kidney disease (PKD). We provide here a basic overview of the origins and clinical aspects of ARPKD and ADPKD and discuss the implications of electrolyte transport in cystogenesis. Special attention is devoted to intracellular calcium handling by the cystic cells, with a focus on polycystins and fibrocystin, as well as other calcium level regulators, such as transient receptor potential vanilloid type 4 (TRPV4) channels, ciliary machinery, and purinergic receptor remodeling. Sodium transport is reviewed with a focus on the epithelial sodium channel (ENaC), and the role of chloride-dependent fluid secretion in cystic fluid accumulation is discussed. In addition, we highlight the emerging promising concepts in the field, such as potassium transport, and suggest some new avenues for research related to electrolyte handling.
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Affiliation(s)
| | | | - Regina F. Sultanova
- Saint-Petersburg State Chemical Pharmaceutical University, St. Petersburg, Russia
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35
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Ishii T, Warabi E, Mann GE. Mechanisms underlying unidirectional laminar shear stress-mediated Nrf2 activation in endothelial cells: Amplification of low shear stress signaling by primary cilia. Redox Biol 2021; 46:102103. [PMID: 34425388 PMCID: PMC8379703 DOI: 10.1016/j.redox.2021.102103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/07/2021] [Accepted: 08/12/2021] [Indexed: 12/14/2022] Open
Abstract
Endothelial cells are sensitive to mechanical stress and respond differently to oscillatory flow versus unidirectional flow. This review highlights the mechanisms by which a wide range of unidirectional laminar shear stress induces activation of the redox sensitive antioxidant transcription factor nuclear factor-E2-related factor 2 (Nrf2) in cultured endothelial cells. We propose that fibroblast growth factor-2 (FGF-2), brain-derived neurotrophic factor (BDNF) and 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) are potential Nrf2 activators induced by laminar shear stress. Shear stress-dependent secretion of FGF-2 and its receptor-mediated signaling is tightly controlled, requiring neutrophil elastase released by shear stress, αvβ3 integrin and the cell surface glycocalyx. We speculate that primary cilia respond to low laminar shear stress (<10 dyn/cm2), resulting in secretion of insulin-like growth factor 1 (IGF-1), which facilitates αvβ3 integrin-dependent FGF-2 secretion. Shear stress induces generation of heparan-binding epidermal growth factor-like growth factor (HB-EGF), which contributes to FGF-2 secretion and gene expression. Furthermore, HB-EGF signaling modulates FGF-2-mediated NADPH oxidase 1 activation that favors casein kinase 2 (CK2)-mediated phosphorylation/activation of Nrf2 associated with caveolin 1 in caveolae. Higher shear stress (>15 dyn/cm2) induces vesicular exocytosis of BDNF from endothelial cells, and we propose that BDNF via the p75NTR receptor could induce CK2-mediated Nrf2 activation. Unidirectional laminar shear stress upregulates gene expression of FGF-2 and BDNF and generation of 15d-PGJ2, which cooperate in sustaining Nrf2 activation to protect endothelial cells against oxidative damage.
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Affiliation(s)
- Tetsuro Ishii
- School of Medicine, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.
| | - Eiji Warabi
- School of Medicine, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.
| | - Giovanni E Mann
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, King's College London, 150 Stamford Street, London, SE1 9NH, UK.
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36
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Vasileva VY, Sultanova RF, Sudarikova AV, Ilatovskaya DV. Insights Into the Molecular Mechanisms of Polycystic Kidney Diseases. Front Physiol 2021; 12:693130. [PMID: 34566674 PMCID: PMC8456103 DOI: 10.3389/fphys.2021.693130] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 08/10/2021] [Indexed: 12/18/2022] Open
Abstract
Autosomal dominant (AD) and autosomal recessive (AR) polycystic kidney diseases (PKD) are severe multisystem genetic disorders characterized with formation and uncontrolled growth of fluid-filled cysts in the kidney, the spread of which eventually leads to the loss of renal function. Currently, there are no treatments for ARPKD, and tolvaptan is the only FDA-approved drug that alleviates the symptoms of ADPKD. However, tolvaptan has only a modest effect on disease progression, and its long-term use is associated with many side effects. Therefore, there is still a pressing need to better understand the fundamental mechanisms behind PKD development. This review highlights current knowledge about the fundamental aspects of PKD development (with a focus on ADPKD) including the PC1/PC2 pathways and cilia-associated mechanisms, major molecular cascades related to metabolism, mitochondrial bioenergetics, and systemic responses (hormonal status, levels of growth factors, immune system, and microbiome) that affect its progression. In addition, we discuss new information regarding non-pharmacological therapies, such as dietary restrictions, which can potentially alleviate PKD.
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Affiliation(s)
| | - Regina F Sultanova
- Saint-Petersburg State Chemical Pharmaceutical University, St. Petersburg, Russia.,Department of Physiology, Augusta University, Augusta, GA, United States
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Role of K + and Ca 2+-Permeable Channels in Osteoblast Functions. Int J Mol Sci 2021; 22:ijms221910459. [PMID: 34638799 PMCID: PMC8509041 DOI: 10.3390/ijms221910459] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 12/20/2022] Open
Abstract
Bone-forming cells or osteoblasts play an important role in bone modeling and remodeling processes. Osteoblast differentiation or osteoblastogenesis is orchestrated by multiple intracellular signaling pathways (e.g., bone morphogenetic proteins (BMP) and Wnt signaling pathways) and is modulated by the extracellular environment (e.g., parathyroid hormone (PTH), vitamin D, transforming growth factor β (TGF-β), and integrins). The regulation of bone homeostasis depends on the proper differentiation and function of osteoblast lineage cells from osteogenic precursors to osteocytes. Intracellular Ca2+ signaling relies on the control of numerous processes in osteoblast lineage cells, including cell growth, differentiation, migration, and gene expression. In addition, hyperpolarization via the activation of K+ channels indirectly promotes Ca2+ signaling in osteoblast lineage cells. An improved understanding of the fundamental physiological and pathophysiological processes in bone homeostasis requires detailed investigations of osteoblast lineage cells. This review summarizes the current knowledge on the functional impacts of K+ channels and Ca2+-permeable channels, which critically regulate Ca2+ signaling in osteoblast lineage cells to maintain bone homeostasis.
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38
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Grosch M, Brunner K, Ilyaskin AV, Schober M, Staudner T, Schmied D, Stumpp T, Schmidt KN, Madej MG, Pessoa TD, Othmen H, Kubitza M, Osten L, de Vries U, Mair MM, Somlo S, Moser M, Kunzelmann K, Ziegler C, Haerteis S, Korbmacher C, Witzgall R. A polycystin-2 protein with modified channel properties leads to an increased diameter of renal tubules and to renal cysts. J Cell Sci 2021; 134:271186. [PMID: 34345895 PMCID: PMC8435292 DOI: 10.1242/jcs.259013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/22/2021] [Indexed: 01/14/2023] Open
Abstract
Mutations in the PKD2 gene cause autosomal-dominant polycystic kidney disease but the physiological role of polycystin-2, the protein product of PKD2, remains elusive. Polycystin-2 belongs to the transient receptor potential (TRP) family of non-selective cation channels. To test the hypothesis that altered ion channel properties of polycystin-2 compromise its putative role in a control circuit controlling lumen formation of renal tubular structures, we generated a mouse model in which we exchanged the pore loop of polycystin-2 with that of the closely related cation channel polycystin-2L1 (encoded by PKD2L1), thereby creating the protein polycystin-2poreL1. Functional characterization of this mutant channel in Xenopus laevis oocytes demonstrated that its electrophysiological properties differed from those of polycystin-2 and instead resembled the properties of polycystin-2L1, in particular regarding its permeability for Ca2+ ions. Homology modeling of the ion translocation pathway of polycystin-2poreL1 argues for a wider pore in polycystin-2poreL1 than in polycystin-2. In Pkd2poreL1 knock-in mice in which the endogenous polycystin-2 protein was replaced by polycystin-2poreL1 the diameter of collecting ducts was increased and collecting duct cysts developed in a strain-dependent fashion. Summary: Replacement of the pore region of polycystin-2 with that of polycystin-2L1 results in wider renal tubules and polycystic kidney disease, thus demonstrating the essential function of its ion channel properties.
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Affiliation(s)
- Melanie Grosch
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
| | - Katrin Brunner
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
| | - Alexandr V Ilyaskin
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Michael Schober
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
| | - Tobias Staudner
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Denise Schmied
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
| | - Tina Stumpp
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
| | - Kerstin N Schmidt
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
| | - M Gregor Madej
- Department of Biophysics, University of Regensburg, 93053 Regensburg, Germany
| | - Thaissa D Pessoa
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Helga Othmen
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
| | - Marion Kubitza
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
| | - Larissa Osten
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
| | - Uwe de Vries
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
| | - Magdalena M Mair
- Faculty of Biology and Preclinical Medicine, University of Regensburg, 93053 Regensburg, Germany
| | - Stefan Somlo
- Departments of Medicine and Genetics, Yale University, New Haven, CT 06520, USA
| | - Markus Moser
- Institute of Experimental Hematology, Technical University of Munich, 81675 Munich, Germany
| | - Karl Kunzelmann
- Department of Physiology, University of Regensburg, 93053 Regensburg, Germany
| | - Christine Ziegler
- Department of Biophysics, University of Regensburg, 93053 Regensburg, Germany
| | - Silke Haerteis
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
| | - Christoph Korbmacher
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Ralph Witzgall
- Institute for Molecular and Cellular Anatomy, University of Regensburg, 93053 Regensburg, Germany
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Structural basis for Ca 2+ activation of the heteromeric PKD1L3/PKD2L1 channel. Nat Commun 2021; 12:4871. [PMID: 34381056 PMCID: PMC8357825 DOI: 10.1038/s41467-021-25216-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 07/23/2021] [Indexed: 02/07/2023] Open
Abstract
The heteromeric complex between PKD1L3, a member of the polycystic kidney disease (PKD) protein family, and PKD2L1, also known as TRPP2 or TRPP3, has been a prototype for mechanistic characterization of heterotetrametric TRP-like channels. Here we show that a truncated PKD1L3/PKD2L1 complex with the C-terminal TRP-fold fragment of PKD1L3 retains both Ca2+ and acid-induced channel activities. Cryo-EM structures of this core heterocomplex with or without supplemented Ca2+ were determined at resolutions of 3.1 Å and 3.4 Å, respectively. The heterotetramer, with a pseudo-symmetric TRP architecture of 1:3 stoichiometry, has an asymmetric selectivity filter (SF) guarded by Lys2069 from PKD1L3 and Asp523 from the three PKD2L1 subunits. Ca2+-entrance to the SF vestibule is accompanied by a swing motion of Lys2069 on PKD1L3. The S6 of PKD1L3 is pushed inward by the S4-S5 linker of the nearby PKD2L1 (PKD2L1-III), resulting in an elongated intracellular gate which seals the pore domain. Comparison of the apo and Ca2+-loaded complexes unveils an unprecedented Ca2+ binding site in the extracellular cleft of the voltage-sensing domain (VSD) of PKD2L1-III, but not the other three VSDs. Structure-guided mutagenic studies support this unconventional site to be responsible for Ca2+-induced channel activation through an allosteric mechanism.
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40
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Cordido A, Vizoso-Gonzalez M, Garcia-Gonzalez MA. Molecular Pathophysiology of Autosomal Recessive Polycystic Kidney Disease. Int J Mol Sci 2021; 22:6523. [PMID: 34204582 PMCID: PMC8235086 DOI: 10.3390/ijms22126523] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/19/2022] Open
Abstract
Autosomal recessive polycystic kidney disease (ARPKD) is a rare disorder and one of the most severe forms of polycystic kidney disease, leading to end-stage renal disease (ESRD) in childhood. PKHD1 is the gene that is responsible for the vast majority of ARPKD. However, some cases have been related to a new gene that was recently identified (DZIP1L gene), as well as several ciliary genes that can mimic a ARPKD-like phenotypic spectrum. In addition, a number of molecular pathways involved in the ARPKD pathogenesis and progression were elucidated using cellular and animal models. However, the function of the ARPKD proteins and the molecular mechanism of the disease currently remain incompletely understood. Here, we review the clinics, treatment, genetics, and molecular basis of ARPKD, highlighting the most recent findings in the field.
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Affiliation(s)
- Adrian Cordido
- Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxía (No. 11), Instituto de Investigación Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain; (A.C.); (M.V.-G.)
- Grupo de Medicina Xenómica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
| | - Marta Vizoso-Gonzalez
- Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxía (No. 11), Instituto de Investigación Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain; (A.C.); (M.V.-G.)
- Grupo de Medicina Xenómica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
| | - Miguel A. Garcia-Gonzalez
- Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxía (No. 11), Instituto de Investigación Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain; (A.C.); (M.V.-G.)
- Grupo de Medicina Xenómica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
- Fundación Publica Galega de Medicina Xenómica-SERGAS, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
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41
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Márquez-Nogueras KM, Hortua Triana MA, Chasen NM, Kuo IY, Moreno SN. Calcium signaling through a transient receptor channel is important for Toxoplasma gondii growth. eLife 2021; 10:63417. [PMID: 34106044 PMCID: PMC8216714 DOI: 10.7554/elife.63417] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 06/08/2021] [Indexed: 12/24/2022] Open
Abstract
Transient receptor potential (TRP) channels participate in calcium ion (Ca2+) influx and intracellular Ca2+ release. TRP channels have not been studied in Toxoplasma gondii or any other apicomplexan parasite. In this work, we characterize TgGT1_310560, a protein predicted to possess a TRP domain (TgTRPPL-2), and determined its role in Ca2+ signaling in T. gondii, the causative agent of toxoplasmosis. TgTRPPL-2 localizes to the plasma membrane and the endoplasmic reticulum (ER) of T. gondii. The ΔTgTRPPL-2 mutant was defective in growth and cytosolic Ca2+ influx from both extracellular and intracellular sources. Heterologous expression of TgTRPPL-2 in HEK-3KO cells allowed its functional characterization. Patching of ER-nuclear membranes demonstrates that TgTRPPL-2 is a non-selective cation channel that conducts Ca2+. Pharmacological blockers of TgTRPPL-2 inhibit Ca2+ influx and parasite growth. This is the first report of an apicomplexan ion channel that conducts Ca2+ and may initiate a Ca2+ signaling cascade that leads to the stimulation of motility, invasion, and egress. TgTRPPL-2 is a potential target for combating toxoplasmosis.
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Affiliation(s)
- Karla Marie Márquez-Nogueras
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, United States.,Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, United States
| | | | - Nathan M Chasen
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, United States
| | - Ivana Y Kuo
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, United States
| | - Silvia Nj Moreno
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, United States.,Department of Cellular Biology, University of Georgia, Athens, United States
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42
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Kleene SJ, Kleene NK. Inward Ca 2+ current through the polycystin-2-dependent channels of renal primary cilia. Am J Physiol Renal Physiol 2021; 320:F1165-F1173. [PMID: 33969696 DOI: 10.1152/ajprenal.00062.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In 15% of cases, autosomal dominant polycystic kidney disease arises from defects in polycystin-2 (PC2). PC2 is a member of the polycystin transient receptor potential subfamily of cation-conducting channels and is expressed in the endoplasmic reticulum and primary cilium of renal epithelial cells. PC2 opposes a procystogenic influence of the cilium, and it has been proposed that this beneficial effect is mediated in part by a flow of Ca2+ through PC2 channels into the primary cilium. However, previous efforts to determine the permeability of PC2 channels to Ca2+ have yielded widely varying results. Here, we report the mean macroscopic Ca2+ influx through native PC2 channels in the primary cilia of mIMCD-3 cells, which are derived from the murine inner medullary collecting duct. Under conditions designed to isolate inward Ca2+ currents, a small inward Ca2+ current was detected in cilia with active PC2 channels but not in cilia lacking those channels. The current was activated by the addition of 10 µM internal Ca2+, which is known to activate ciliary PC2 channels. It was blocked by 10 µM isosakuranetin, which blocks the same channels. On average, the current amplitude was -1.8 pA at -190 mV; its conductance from -50 to -200 mV averaged 20 pS. Thus, native PC2 channels of renal primary cilia are able to conduct a small but detectable Ca2+ influx under the conditions tested. The possible consequences of this influx are discussed.NEW & NOTEWORTHY In autosomal dominant polycystic kidney disease, it is proposed that Ca2+ entering the primary cilium through polycystin-2 (PC2) channels may limit the formation of cysts. Recent studies predict that any macroscopic Ca2+ influx through these channels should be small. We report that the native PC2 channels in primary cilia of cultured renal epithelial cells can allow a small macroscopic calcium influx. This may allow a significant accumulation of Ca2+ in the cilium in vivo.
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Affiliation(s)
- Steven J Kleene
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio
| | - Nancy K Kleene
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio
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43
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Duong Phu M, Bross S, Burkhalter MD, Philipp M. Limitations and opportunities in the pharmacotherapy of ciliopathies. Pharmacol Ther 2021; 225:107841. [PMID: 33771583 DOI: 10.1016/j.pharmthera.2021.107841] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/11/2021] [Indexed: 01/10/2023]
Abstract
Ciliopathies are a family of rather diverse conditions, which have been grouped based on the finding of altered or dysfunctional cilia, potentially motile, small cellular antennae extending from the surface of postmitotic cells. Cilia-related disorders include embryonically arising conditions such as Joubert, Usher or Kartagener syndrome, but also afflictions with a postnatal or even adult onset phenotype, i.e. autosomal dominant polycystic kidney disease. The majority of ciliopathies are syndromic rather than affecting only a single organ due to cilia being found on almost any cell in the human body. Overall ciliopathies are considered rare diseases. Despite that, pharmacological research and the strive to help these patients has led to enormous therapeutic advances in the last decade. In this review we discuss new treatment options for certain ciliopathies, give an outlook on promising future therapeutic strategies, but also highlight the limitations in the development of therapeutic approaches of ciliopathies.
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Affiliation(s)
- Max Duong Phu
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany
| | - Stefan Bross
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany
| | - Martin D Burkhalter
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany
| | - Melanie Philipp
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany.
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44
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Ha K, Nobuhara M, Wang Q, Walker RV, Qian F, Schartner C, Cao E, Delling M. The heteromeric PC-1/PC-2 polycystin complex is activated by the PC-1 N-terminus. eLife 2020; 9:60684. [PMID: 33164752 PMCID: PMC7728438 DOI: 10.7554/elife.60684] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 11/06/2020] [Indexed: 12/28/2022] Open
Abstract
Mutations in the polycystin proteins, PC-1 and PC-2, result in autosomal dominant polycystic kidney disease (ADPKD) and ultimately renal failure. PC-1 and PC-2 enrich on primary cilia, where they are thought to form a heteromeric ion channel complex. However, a functional understanding of the putative PC-1/PC-2 polycystin complex is lacking due to technical hurdles in reliably measuring its activity. Here we successfully reconstitute the PC-1/PC-2 complex in the plasma membrane of mammalian cells and show that it functions as an outwardly rectifying channel. Using both reconstituted and ciliary polycystin channels, we further show that a soluble fragment generated from the N-terminal extracellular domain of PC-1 functions as an intrinsic agonist that is necessary and sufficient for channel activation. We thus propose that autoproteolytic cleavage of the N-terminus of PC-1, a hotspot for ADPKD mutations, produces a soluble ligand in vivo. These findings establish a mechanistic framework for understanding the role of PC-1/PC-2 heteromers in ADPKD and suggest new therapeutic strategies that would expand upon the limited symptomatic treatments currently available for this progressive, terminal disease. On the surface of most animal and other eukaryotic cells are small rod-like protrusions known as primary cilia. Each cilium is encased by a specialized membrane which is enriched in protein complexes that help the cell sense its local environment. Some of these complexes help transport ions in out of the cell, while others act as receptors that receive chemical signals called ligands. A unique ion channel known as the polycystin complex is able to perform both of these roles as it contains a receptor called PC-1 in addition to an ion channel called PC-2. Various mutations in the genes that code for PC-1 and PC-2 can result in autosomal dominant polycystic kidney disease (ADPKD), which is the most common monogenetic disease in humans. However, due to the small size of primary cilia – which are less than a thousandth of a millimeter thick – little is known about how polycystin complexes are regulated and how mutations lead to ADPKD. To overcome this barrier, Ha et al. modified kidney cells grown in the lab so that PC-1 and PC-2 form a working channel in the plasma membrane which surrounds the entire cell. As the body of a cell is around 10,000 times bigger than the cilium, this allowed the movement of ions across the polycystin complex to be studied using conventional techniques. Experiments using this newly developed assay revealed that a region at one of the ends of the PC-1 protein, named the C-type lectin domain, is essential for stimulating polycystin complexes. Ha et al. found that this domain of PC-1 is able to cut itself from the protein complex. Further experiments showed that when fragments of PC-1, which contain the C-type lectin domain, are no longer bound to the membrane, they can activate the polycystin channels in cilia as well as the plasma membrane. This suggests that this region of PC-1 may also act as a secreted ligand that can activate other polycystin channels. Some of the genetic mutations that cause ADPKD likely disrupt the activity of the polycystin complex and reduce its ability to transport ions across the cilia membrane. Therefore, the cell assay created in this study could be used to screen for small molecules that can restore the activity of these ion channels in patients with ADPKD.
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Affiliation(s)
- Kotdaji Ha
- Department of Physiology, University of California, San Francisco, San Francisco, United States
| | - Mai Nobuhara
- Department of Physiology, University of California, San Francisco, San Francisco, United States
| | - Qinzhe Wang
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Rebecca V Walker
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, United States
| | - Feng Qian
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, United States
| | - Christoph Schartner
- Department of Physiology, University of California, San Francisco, San Francisco, United States
| | - Erhu Cao
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Markus Delling
- Department of Physiology, University of California, San Francisco, San Francisco, United States
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45
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Shao L, El-Jouni W, Kong F, Ramesh J, Kumar RS, Shen X, Ren J, Devendra S, Dorschel A, Wu M, Barrera I, Tabari A, Hu K, Haque N, Yambayev I, Li S, Kumar A, Behera TR, McDonough G, Furuichi M, Xifaras M, Lu T, Alhayaza RM, Miyabayashi K, Fan Q, Ajay AK, Zhou J. Genetic reduction of cilium length by targeting intraflagellar transport 88 protein impedes kidney and liver cyst formation in mouse models of autosomal polycystic kidney disease. Kidney Int 2020; 98:1225-1241. [DOI: 10.1016/j.kint.2020.05.049] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/23/2020] [Accepted: 05/28/2020] [Indexed: 12/31/2022]
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46
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McConnachie DJ, Stow JL, Mallett AJ. Ciliopathies and the Kidney: A Review. Am J Kidney Dis 2020; 77:410-419. [PMID: 33039432 DOI: 10.1053/j.ajkd.2020.08.012] [Citation(s) in RCA: 111] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/11/2020] [Indexed: 12/19/2022]
Abstract
Primary cilia are specialized sensory organelles that protrude from the apical surface of most cell types. During the past 2 decades, they have been found to play important roles in tissue development and signal transduction, with mutations in ciliary-associated proteins resulting in a group of diseases collectively known as ciliopathies. Many of these mutations manifest as renal ciliopathies, characterized by kidney dysfunction resulting from aberrant cilia or ciliary functions. This group of overlapping and genetically heterogeneous diseases includes polycystic kidney disease, nephronophthisis, and Bardet-Biedl syndrome as the main focus of this review. Renal ciliopathies are characterized by the presence of kidney cysts that develop due to uncontrolled epithelial cell proliferation, growth, and polarity, downstream of dysregulated ciliary-dependent signaling. Due to cystic-associated kidney injury and systemic inflammation, cases result in kidney failure requiring dialysis and transplantation. Of the handful of pharmacologic treatments available, none are curative. It is important to determine the molecular mechanisms that underlie the involvement of the primary cilium in cyst initiation, expansion, and progression for the development of novel and efficacious treatments. This review updates research progress in defining key genes and molecules central to ciliogenesis and renal ciliopathies.
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Affiliation(s)
- Dominique J McConnachie
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation Disease and Research, The University of Queensland, Brisbane, QLD, Australia
| | - Jennifer L Stow
- Kidney Health Service, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
| | - Andrew J Mallett
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation Disease and Research, The University of Queensland, Brisbane, QLD, Australia; Kidney Health Service, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia; Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia; KidGen Collaborative, Australian Genomics Health Alliance, Melbourne, VIC, Australia.
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Cai R, Liu X, Zhang R, Hofmann L, Zheng W, Amin MR, Wang L, Hu Q, Peng JB, Michalak M, Flockerzi V, Ali DW, Chen XZ, Tang J. Autoinhibition of TRPV6 Channel and Regulation by PIP2. iScience 2020; 23:101444. [PMID: 32829285 PMCID: PMC7452202 DOI: 10.1016/j.isci.2020.101444] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/07/2020] [Accepted: 08/04/2020] [Indexed: 12/30/2022] Open
Abstract
Transient receptor potential vanilloid 6 (TRPV6), a calcium-selective channel possessing six transmembrane domains (S1-S6) and intracellular N and C termini, plays crucial roles in calcium absorption in epithelia and bone and is involved in human diseases including vitamin-D deficiency, osteoporosis, and cancer. The TRPV6 function and regulation remain poorly understood. Here we show that the TRPV6 intramolecular S4-S5 linker to C-terminal TRP helix (L/C) and N-terminal pre-S1 helix to TRP helix (N/C) interactions, mediated by Arg470:Trp593 and Trp321:Ile597 bonding, respectively, are autoinhibitory and are required for maintaining TRPV6 at basal states. Disruption of either interaction by mutations or blocking peptides activates TRPV6. The N/C interaction depends on the L/C interaction but not reversely. Three cationic residues in S5 or C terminus are involved in binding PIP2 to suppress both interactions thereby activating TRPV6. This study reveals "PIP2 - intramolecular interactions" regulatory mechanism of TRPV6 activation-autoinhibition, which will help elucidating the corresponding mechanisms in other TRP channels.
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Affiliation(s)
- Ruiqi Cai
- National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei 430068, China
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Xiong Liu
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Rui Zhang
- National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei 430068, China
| | - Laura Hofmann
- Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, 66421 Homburg, Germany
| | - Wang Zheng
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Md Ruhul Amin
- Department of Biological Sciences, Biological Sciences Building, University of Alberta, T6G 2E9 Edmonton, AB, Canada
| | - Lingyun Wang
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Qiaolin Hu
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Ji-Bin Peng
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Marek Michalak
- Membrane Protein Disease Research Group, Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Veit Flockerzi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, 66421 Homburg, Germany
| | - Declan W. Ali
- Department of Biological Sciences, Biological Sciences Building, University of Alberta, T6G 2E9 Edmonton, AB, Canada
| | - Xing-Zhen Chen
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Jingfeng Tang
- National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei 430068, China
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48
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Hu J, Harris PC. Regulation of polycystin expression, maturation and trafficking. Cell Signal 2020; 72:109630. [PMID: 32275942 PMCID: PMC7269868 DOI: 10.1016/j.cellsig.2020.109630] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/03/2020] [Accepted: 04/04/2020] [Indexed: 12/26/2022]
Abstract
The major autosomal dominant polycystic kidney disease (ADPKD) genes, PKD1 and PKD2, are wildly expressed at the organ and tissue level. PKD1 encodes polycystin 1 (PC1), a large membrane associated receptor-like protein that can complex with the PKD2 product, PC2. Various cellular locations have been described for both PC1, including the plasma membrane and extracellular vesicles, and PC2, especially the endoplasmic reticulum (ER), but compelling evidence indicates that the primary cilium, a sensory organelle, is the key site for the polycystin complex to prevent PKD. As with other membrane proteins, the ER biogenesis pathway is key to appropriately folding, performing quality control, and exporting fully folded PC1 to the Golgi apparatus. There is a requirement for binding with PC2 and cleavage of PC1 at the GPS for this folding and export to occur. Six different monogenic defects in this pathway lead to cystic disease development, with PC1 apparently particularly sensitive to defects in this general protein processing pathway. Trafficking of membrane proteins, and the polycystins in particular, through the Golgi to the primary cilium have been analyzed in detail, but at this time, there is no clear consensus on a ciliary targeting sequence required to export proteins to the cilium. After transitioning though the trans-Golgi network, polycystin-bearing vesicles are likely sorted to early or recycling endosomes and then transported to the ciliary base, possibly via docking to transition fibers (TF). The membrane-bound polycystin complex then undergoes facilitated trafficking through the transition zone, the diffusion barrier at the base of the cilium, before entering the cilium. Intraflagellar transport (IFT) may be involved in moving the polycystins along the cilia, but data also indicates other mechanisms. The ciliary polycystin complex can be ubiquitinated and removed from cilia by internalization at the ciliary base and may be sent back to the plasma membrane for recycling or to lysosomes for degradation. Monogenic defects in processes regulating the protein composition of cilia are associated with syndromic disorders involving many organ systems, reflecting the pleotropic role of cilia during development and for tissue maintenance. Many of these ciliopathies have renal involvement, likely because of faulty polycystin signaling from cilia. Understanding the expression, maturation and trafficking of the polycystins helps understand PKD pathogenesis and suggests opportunities for therapeutic intervention.
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Affiliation(s)
- Jinghua Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA; Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.
| | - Peter C Harris
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA; Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.
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49
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Padovano V, Mistry K, Merrick D, Gresko N, Caplan MJ. A cut above (and below): Protein cleavage in the regulation of polycystin trafficking and signaling. Cell Signal 2020; 72:109634. [PMID: 32283256 PMCID: PMC7269866 DOI: 10.1016/j.cellsig.2020.109634] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 10/24/2022]
Abstract
The polycystin-1 and 2 proteins, encoded by the genes mutated in Autosomal Dominant Polycystic Kidney Disease, are connected to a large number of biological pathways. While the nature of these connections and their relevance to the primary functions of the polycystin proteins have yet to be fully elucidated, it is clear that many of them are mediated by or depend upon cleavage of the polycystin-1 protein. Cleavage of polycystin-1 at its G protein coupled receptor proteolytic site is an obligate step in the protein's maturation and in aspects of its trafficking. This cleavage may also serve to prime polycystin-1 to play a role as a non-canonical G protein coupled receptor. Cleavage of the cytoplasmic polycystin-1C terminal tail releases fragments that are able to enter the nucleus and the mitochondria and to influence their activities. Understanding the nature of these cleavages, their regulation and their consequences is likely to provide valuable insights into both the physiological functions served by the polycystin proteins and the pathological consequences of their absence.
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Affiliation(s)
- Valeria Padovano
- Broad Institute of MIT and Harvard, Massachusetts Institute of Technology, 415 Main Street, Cambridge, MA 02142, USA
| | - Kavita Mistry
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520-8026, USA
| | - David Merrick
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520-8026, USA
| | - Nikolay Gresko
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520-8026, USA
| | - Michael J Caplan
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520-8026, USA.
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50
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MacKay CE, Leo MD, Fernández-Peña C, Hasan R, Yin W, Mata-Daboin A, Bulley S, Gammons J, Mancarella S, Jaggar JH. Intravascular flow stimulates PKD2 (polycystin-2) channels in endothelial cells to reduce blood pressure. eLife 2020; 9:56655. [PMID: 32364494 PMCID: PMC7228764 DOI: 10.7554/elife.56655] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/04/2020] [Indexed: 02/07/2023] Open
Abstract
PKD2 (polycystin-2, TRPP1), a TRP polycystin channel, is expressed in endothelial cells (ECs), but its physiological functions in this cell type are unclear. Here, we generated inducible, EC-specific Pkd2 knockout mice to examine vascular functions of PKD2. Data show that a broad range of intravascular flow rates stimulate EC PKD2 channels, producing vasodilation. Flow-mediated PKD2 channel activation leads to calcium influx that activates SK/IK channels and eNOS serine 1176 phosphorylation in ECs. These signaling mechanisms produce arterial hyperpolarization and vasodilation. In contrast, EC PKD2 channels do not contribute to acetylcholine-induced vasodilation, suggesting stimulus-specific function. EC-specific PKD2 knockout elevated blood pressure in mice without altering cardiac function or kidney anatomy. These data demonstrate that flow stimulates PKD2 channels in ECs, leading to SK/IK channel and eNOS activation, hyperpolarization, vasodilation and a reduction in systemic blood pressure. Thus, PKD2 channels are a major component of functional flow sensing in the vasculature.
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Affiliation(s)
- Charles E MacKay
- Department of Physiology University of Tennessee Health Science Center Memphis, Memphis, United States
| | - M Dennis Leo
- Department of Physiology University of Tennessee Health Science Center Memphis, Memphis, United States
| | - Carlos Fernández-Peña
- Department of Physiology University of Tennessee Health Science Center Memphis, Memphis, United States
| | - Raquibul Hasan
- Department of Physiology University of Tennessee Health Science Center Memphis, Memphis, United States
| | - Wen Yin
- Department of Physiology University of Tennessee Health Science Center Memphis, Memphis, United States
| | - Alejandro Mata-Daboin
- Department of Physiology University of Tennessee Health Science Center Memphis, Memphis, United States
| | - Simon Bulley
- Department of Physiology University of Tennessee Health Science Center Memphis, Memphis, United States
| | - Jesse Gammons
- Department of Physiology University of Tennessee Health Science Center Memphis, Memphis, United States
| | - Salvatore Mancarella
- Department of Physiology University of Tennessee Health Science Center Memphis, Memphis, United States
| | - Jonathan H Jaggar
- Department of Physiology University of Tennessee Health Science Center Memphis, Memphis, United States
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