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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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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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Wu JY, Cho SJ, Descant K, Li PH, Shapson-Coe A, Januszewski M, Berger DR, Meyer C, Casingal C, Huda A, Liu J, Ghashghaei T, Brenman M, Jiang M, Scarborough J, Pope A, Jain V, Stein JL, Guo J, Yasuda R, Lichtman JW, Anton ES. Mapping of neuronal and glial primary cilia contactome and connectome in the human cerebral cortex. Neuron 2024; 112:41-55.e3. [PMID: 37898123 PMCID: PMC10841524 DOI: 10.1016/j.neuron.2023.09.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 07/25/2023] [Accepted: 09/22/2023] [Indexed: 10/30/2023]
Abstract
Primary cilia act as antenna receivers of environmental signals and enable effective neuronal or glial responses. Disruption of their function is associated with circuit disorders. To understand the signals these cilia receive, we comprehensively mapped cilia's contacts within the human cortical connectome using serial-section EM reconstruction of a 1 mm3 cortical volume, spanning the entire cortical thickness. We mapped the "contactome" of cilia emerging from neurons and astrocytes in every cortical layer. Depending on the layer and cell type, cilia make distinct patterns of contact. Primary cilia display cell-type- and layer-specific variations in size, shape, and microtubule axoneme core, which may affect their signaling competencies. Neuronal cilia are intrinsic components of a subset of cortical synapses and thus a part of the connectome. This diversity in the structure, contactome, and connectome of primary cilia endows each neuron or glial cell with a unique barcode of access to the surrounding neural circuitry.
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Affiliation(s)
- Jun Yao Wu
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Su-Ji Cho
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Katherine Descant
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Peter H Li
- Google Research, Mountain View, CA 94043, USA
| | - Alexander Shapson-Coe
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | | | - Daniel R Berger
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Cailyn Meyer
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Cristine Casingal
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Ariba Huda
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Jiaqi Liu
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Tina Ghashghaei
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Mikayla Brenman
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Michelle Jiang
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Joseph Scarborough
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Art Pope
- Google Research, Mountain View, CA 94043, USA
| | - Viren Jain
- Google Research, Mountain View, CA 94043, USA
| | - Jason L Stein
- UNC Neuroscience Center and the Department of Genetics, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Jiami Guo
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA.
| | - Jeff W Lichtman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
| | - E S Anton
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
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Mill P, Christensen ST, Pedersen LB. Primary cilia as dynamic and diverse signalling hubs in development and disease. Nat Rev Genet 2023; 24:421-441. [PMID: 37072495 PMCID: PMC7615029 DOI: 10.1038/s41576-023-00587-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2023] [Indexed: 04/20/2023]
Abstract
Primary cilia, antenna-like sensory organelles protruding from the surface of most vertebrate cell types, are essential for regulating signalling pathways during development and adult homeostasis. Mutations in genes affecting cilia cause an overlapping spectrum of >30 human diseases and syndromes, the ciliopathies. Given the immense structural and functional diversity of the mammalian cilia repertoire, there is a growing disconnect between patient genotype and associated phenotypes, with variable severity and expressivity characteristic of the ciliopathies as a group. Recent technological developments are rapidly advancing our understanding of the complex mechanisms that control biogenesis and function of primary cilia across a range of cell types and are starting to tackle this diversity. Here, we examine the structural and functional diversity of primary cilia, their dynamic regulation in different cellular and developmental contexts and their disruption in disease.
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Affiliation(s)
- Pleasantine Mill
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
| | | | - Lotte B Pedersen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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Pan J. Cilia are not created equal-restriction of IFT on microtubule tracks for cilia diversification. Bioessays 2022; 44:e2200082. [PMID: 35595681 DOI: 10.1002/bies.202200082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Junmin Pan
- MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong Province, China
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