1
|
Sun K, Liu L, Jiang X, Wang H, Wang L, Yang Y, Liu W, Zhang L, Zhao X, Zhu X. The endoplasmic reticulum membrane protein complex subunit Emc6 is essential for rhodopsin localization and photoreceptor cell survival. Genes Dis 2024; 11:1035-1049. [PMID: 37692493 PMCID: PMC10492031 DOI: 10.1016/j.gendis.2023.03.033] [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: 09/21/2022] [Revised: 02/17/2023] [Accepted: 03/29/2023] [Indexed: 09/12/2023] Open
Abstract
The endoplasmic reticulum (ER) membrane protein complex (EMC) is responsible for monitoring the biogenesis and synthetic quality of membrane proteins with tail-anchored or multiple transmembrane domains. The EMC subunit EMC6 is one of the core members of EMC and forms an enclosed hydrophilic vestibule in cooperation with EMC3. Despite studies demonstrating that deletion of EMC3 led to rhodopsin mislocalization in rod photoreceptors of mice, the precise mechanism leading to the failure of rhodopsin trafficking remains unclear. Here, we generated the first rod photoreceptor-specific knockout of Emc6 (RKO) and cone photoreceptor-specific knockout of Emc6 (CKO) mouse models. Deficiency of Emc6 in rod photoreceptors led to progressive shortening of outer segments (OS), impaired visual function, mislocalization and reduced expression of rhodopsin, and increased gliosis in rod photoreceptors. In addition, CKO mice displayed the progressive death of cone photoreceptors and abnormal localization of cone opsin protein. Subsequently, proteomics analysis of the RKO mouse retina illustrated that several cilium-related proteins, particularly anoctamin-2 (ANO2) and transmembrane protein 67 (TMEM67), were significantly down-regulated prior to OS degeneration. Detrimental rod photoreceptor cilia and mislocalized membrane disc proteins were evident in RKO mice. Our data revealed that in addition to monitoring the synthesis of rhodopsin-dominated membrane disc proteins, EMC6 also impacted rod photoreceptors' ciliogenesis by regulating the synthesis of membrane proteins associated with cilia, contributing to the mislocalization of membrane disc proteins.
Collapse
Affiliation(s)
- Kuanxiang Sun
- Health Management Center, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Key Laboratory of Tibetan Medicine Research, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Xining, Qinghai 810008, China
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Lu Liu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Xiaoyan Jiang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Heting Wang
- Health Management Center, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Lin Wang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Yeming Yang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Wenjing Liu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Lin Zhang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Xiaohui Zhao
- Key Laboratory of Tibetan Medicine Research, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Xining, Qinghai 810008, China
| | - Xianjun Zhu
- Health Management Center, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Key Laboratory of Tibetan Medicine Research, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Xining, Qinghai 810008, China
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
- Department of Ophthalmology, The First People's Hospital of Shangqiu, Shangqiu, Henan 476000, China
| |
Collapse
|
2
|
Life-Saver or Undertaker: The Relationship between Primary Cilia and Cell Death in Vertebrate Embryonic Development. J Dev Biol 2022; 10:jdb10040052. [PMID: 36547474 PMCID: PMC9783631 DOI: 10.3390/jdb10040052] [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: 10/29/2022] [Revised: 12/02/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
The development of multicellular organisms requires a tightly coordinated network of cellular processes and intercellular signalling. For more than 20 years, it has been known that primary cilia are deeply involved in the mediation of intercellular signalling and that ciliary dysfunction results in severe developmental defects. Cilia-mediated signalling regulates cellular processes such as proliferation, differentiation, migration, etc. Another cellular process ensuring proper embryonic development is cell death. While the effect of cilia-mediated signalling on many cellular processes has been extensively studied, the relationship between primary cilia and cell death remains largely unknown. This article provides a short review on the current knowledge about this relationship.
Collapse
|
3
|
Potter VL, Moye AR, Robichaux MA, Wensel TG. Super-resolution microscopy reveals photoreceptor-specific subciliary location and function of ciliopathy-associated protein CEP290. JCI Insight 2021; 6:e145256. [PMID: 34520396 PMCID: PMC8564900 DOI: 10.1172/jci.insight.145256] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 09/08/2021] [Indexed: 01/19/2023] Open
Abstract
Mutations in the cilium-associated protein CEP290 cause retinal degeneration as part of multiorgan ciliopathies or as retina-specific diseases. The precise location and the functional roles of CEP290 within cilia and, specifically, the connecting cilia (CC) of photoreceptors, remain unclear. We used super-resolution fluorescence microscopy and electron microscopy to localize CEP290 in the CC and in the primary cilia of cultured cells with subdiffraction resolution and to determine effects of CEP290 deficiency in 3 mutant models. Radially, CEP290 localizes in close proximity to the microtubule doublets in the region between the doublets and the ciliary membrane. Longitudinally, it is distributed throughout the length of the CC whereas it is confined to the very base of primary cilia in human retinal pigment epithelium-1 cells. We found Y-shaped links, ciliary substructures between microtubules and membrane, throughout the length of the CC. Severe CEP290 deficiencies in mouse models did not prevent assembly of cilia or cause obvious mislocalization of ciliary components in early stages of degeneration. There were fewer cilia and no normal outer segments in the mutants, but the Y-shaped links were clearly present. These results point to photoreceptor-specific functions of CEP290 essential for CC maturation and stability following the earliest stages of ciliogenesis.
Collapse
Affiliation(s)
- Valencia L Potter
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology.,Program in Developmental Biology, Graduate School of Biomedical Sciences, and.,Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas, USA
| | - Abigail R Moye
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology
| | - Michael A Robichaux
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology.,Departments of Ophthalmology and Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology
| |
Collapse
|
4
|
Ge W, Yan ZH, Wang L, Tan SJ, Liu J, Reiter RJ, Luo SM, Sun QY, Shen W. A hypothetical role for autophagy during the day/night rhythm-regulated melatonin synthesis in the rat pineal gland. J Pineal Res 2021; 71:e12742. [PMID: 33960014 DOI: 10.1111/jpi.12742] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 04/12/2021] [Accepted: 04/27/2021] [Indexed: 12/18/2022]
Abstract
Melatonin is a highly conserved molecule that regulates day/night rhythms; it is associated with sleep improvement, reactive oxygen species (ROS) scavenging, anti-aging effects, and seasonal and circadian rhythms and has been a hot topic of research for decades. Using single-cell RNA sequencing, a recent study describes a single-cell transcriptome atlas for the rat pineal gland. Based on a more comprehensive analysis of the retrieved data (Mays et al., PLoS One, 2018, 13, e0205883), results from the current study unveiled the underappreciated gene regulatory network behind different cell populations in the pineal gland. More importantly, our study here characterized, for the first time, the day/night activation of autophagy flux in the rat pineal gland, indicating a potential role of autophagy in regulating melatonin synthesis in the rat pineal gland. These findings emphasized a hypothetical role of day/night autophagy in linking the biological clock with melatonin synthesis. Furthermore, ultrastructure analysis of pinealocytes provided fascinating insights into differences in their intracellular structure between daytime and nighttime. In addition, we also provide a preliminary description of cell-cell communication in the rat pineal gland. In summary, the current study unveils the day/night regulation of autophagy in the rat pineal gland, raising a potential role of autophagy in day/night-regulated melatonin synthesis.
Collapse
Affiliation(s)
- Wei Ge
- Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Zi-Hui Yan
- Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Lu Wang
- Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Shao-Jing Tan
- Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Jing Liu
- Central Laboratory of Qingdao Agricultural University, Qingdao Agricultural University, Qingdao, China
| | - Russel J Reiter
- Department of Cell Systems and Anatomy, Long School of Medicine, UT Health, San Antonio, TX, USA
| | - Shi-Ming Luo
- Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Qing-Yuan Sun
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Wei Shen
- Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| |
Collapse
|
5
|
Skiba NP, Cady MA, Molday L, Han JYS, Lewis TR, Spencer WJ, Thompson WJ, Hiles S, Philp NJ, Molday RS, Arshavsky VY. TMEM67, TMEM237, and Embigin in Complex With Monocarboxylate Transporter MCT1 Are Unique Components of the Photoreceptor Outer Segment Plasma Membrane. Mol Cell Proteomics 2021; 20:100088. [PMID: 33933680 PMCID: PMC8167285 DOI: 10.1016/j.mcpro.2021.100088] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/25/2021] [Accepted: 04/26/2021] [Indexed: 01/18/2023] Open
Abstract
The outer segment (OS) organelle of vertebrate photoreceptors is a highly specialized cilium evolved to capture light and initiate light response. The plasma membrane which envelopes the OS plays vital and diverse roles in supporting photoreceptor function and health. However, little is known about the identity of its protein constituents, as this membrane cannot be purified to homogeneity. In this study, we used the technique of protein correlation profiling to identify unique OS plasma membrane proteins. To achieve this, we used label-free quantitative MS to compare relative protein abundances in an enriched preparation of the OS plasma membrane with a preparation of total OS membranes. We have found that only five proteins were enriched at the same level as previously validated OS plasma membrane markers. Two of these proteins, TMEM67 and TMEM237, had not been previously assigned to this membrane, and one, embigin, had not been identified in photoreceptors. We further showed that embigin associates with monocarboxylate transporter MCT1 in the OS plasma membrane, facilitating lactate transport through this cellular compartment.
Collapse
Affiliation(s)
- Nikolai P Skiba
- Albert Eye Research Institute, Duke University Medical Center, Durham, North Carolina, USA.
| | - Martha A Cady
- Albert Eye Research Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Laurie Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - John Y S Han
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Tylor R Lewis
- Albert Eye Research Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - William J Spencer
- Albert Eye Research Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Will J Thompson
- Duke Proteomics and Metabolomics Shared Resource, Duke University, Durham, North Carolina, USA
| | - Sarah Hiles
- Duke Proteomics and Metabolomics Shared Resource, Duke University, Durham, North Carolina, USA
| | - Nancy J Philp
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vadim Y Arshavsky
- Albert Eye Research Institute, Duke University Medical Center, Durham, North Carolina, USA.
| |
Collapse
|
6
|
Seo S, Datta P. Photoreceptor outer segment as a sink for membrane proteins: hypothesis and implications in retinal ciliopathies. Hum Mol Genet 2017; 26:R75-R82. [PMID: 28453661 DOI: 10.1093/hmg/ddx163] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 04/24/2017] [Indexed: 12/28/2022] Open
Abstract
The photoreceptor outer segment (OS) is a unique modification of the primary cilium, specialized for light perception. Being homologous organelles, the primary cilium and the OS share common building blocks and molecular machinery to construct and maintain them. The OS, however, has several unique structural features that are not seen in primary cilia. Although these unique features of the OS have been well documented, their implications in protein localization have been under-appreciated. In this review, we compare the structural properties of the primary cilium and the OS, and propose a hypothesis that the OS can act as a sink for membrane proteins. We further discuss the implications of this hypothesis in polarized protein localization in photoreceptors and mechanisms of photoreceptor degeneration in retinal ciliopathies.
Collapse
Affiliation(s)
- Seongjin Seo
- Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Poppy Datta
- Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| |
Collapse
|
7
|
Arango-Gonzalez B, Trifunović D, Sahaboglu A, Kranz K, Michalakis S, Farinelli P, Koch S, Koch F, Cottet S, Janssen-Bienhold U, Dedek K, Biel M, Zrenner E, Euler T, Ekström P, Ueffing M, Paquet-Durand F. Identification of a common non-apoptotic cell death mechanism in hereditary retinal degeneration. PLoS One 2014; 9:e112142. [PMID: 25392995 PMCID: PMC4230983 DOI: 10.1371/journal.pone.0112142] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 10/13/2014] [Indexed: 01/10/2023] Open
Abstract
Cell death in neurodegenerative diseases is often thought to be governed by apoptosis; however, an increasing body of evidence suggests the involvement of alternative cell death mechanisms in neuronal degeneration. We studied retinal neurodegeneration using 10 different animal models, covering all major groups of hereditary human blindness (rd1, rd2, rd10, Cngb1 KO, Rho KO, S334ter, P23H, Cnga3 KO, cpfl1, Rpe65 KO), by investigating metabolic processes relevant for different forms of cell death. We show that apoptosis plays only a minor role in the inherited forms of retinal neurodegeneration studied, where instead, a non-apoptotic degenerative mechanism common to all mutants is of major importance. Hallmark features of this pathway are activation of histone deacetylase, poly-ADP-ribose-polymerase, and calpain, as well as accumulation of cyclic guanosine monophosphate and poly-ADP-ribose. Our work thus demonstrates the prevalence of alternative cell death mechanisms in inherited retinal degeneration and provides a rational basis for the design of mutation-independent treatments.
Collapse
Affiliation(s)
| | - Dragana Trifunović
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Ayse Sahaboglu
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Katharina Kranz
- Department of Neurobiology, University of Oldenburg, Oldenburg, Germany
| | - Stylianos Michalakis
- Center for Integrated Protein Science Munich and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Pietro Farinelli
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Division of Ophthalmology, Department of Clinical Sciences, University of Lund, Lund, Sweden
| | - Susanne Koch
- Center for Integrated Protein Science Munich and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Fred Koch
- Center for Integrated Protein Science Munich and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Sandra Cottet
- Institute for Research in Ophthalmology, Sion, Switzerland
| | | | - Karin Dedek
- Department of Neurobiology, University of Oldenburg, Oldenburg, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Eberhart Zrenner
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Centre for Integrative Neuroscience, University of Tuebingen, Tuebingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
- Centre for Integrative Neuroscience, University of Tuebingen, Tuebingen, Germany
| | - Per Ekström
- Division of Ophthalmology, Department of Clinical Sciences, University of Lund, Lund, Sweden
| | - Marius Ueffing
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | | |
Collapse
|
8
|
Abstract
The primary cilium compartmentalizes a tiny fraction of the cell surface and volume, yet many proteins are highly enriched in this area and so efficient mechanisms are necessary to concentrate them in the ciliary compartment. Here we review mechanisms that are thought to deliver protein cargo to the base of cilia and are likely to interact with ciliary gating mechanisms. Given the immense variety of ciliary cytosolic and transmembrane proteins, it is almost certain that multiple, albeit frequently interconnected, pathways mediate this process. It is also clear that none of these pathways is fully understood at the present time. Mechanisms that are discussed below facilitate ciliary localization of structural and signaling molecules, which include receptors, G-proteins, ion channels, and enzymes. These mechanisms form a basis for every aspect of cilia function in early embryonic patterning, organ morphogenesis, sensory perception and elsewhere.
Collapse
Affiliation(s)
- Jarema Malicki
- MRC Centre for Developmental and Biomedical Genetics; Department of Biomedical Science; The University of Sheffield; Sheffield, UK
| | | |
Collapse
|