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Wang J, Saul J, Nikonorova IA, Cruz CN, Power KM, Nguyen KC, Hall DH, Barr MM. Ciliary intrinsic mechanisms regulate dynamic ciliary extracellular vesicle release from sensory neurons. Curr Biol 2024; 34:2756-2763.e2. [PMID: 38838665 PMCID: PMC11187650 DOI: 10.1016/j.cub.2024.05.015] [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: 11/01/2023] [Revised: 04/02/2024] [Accepted: 05/08/2024] [Indexed: 06/07/2024]
Abstract
Extracellular vesicles (EVs) are submicron membranous structures and key mediators of intercellular communication.1,2 Recent research has highlighted roles for cilia-derived EVs in signal transduction, underscoring their importance as bioactive extracellular organelles containing conserved ciliary signaling proteins.3,4 Members of the transient receptor potential (TRP) channel polycystin-2 (PKD-2) family are found in ciliary EVs of the green algae Chlamydomonas and the nematode Caenorhabditis elegans5,6 and in EVs in the mouse embryonic node and isolated from human urine.7,8 In C. elegans, PKD-2 is expressed in male-specific EV-releasing sensory neurons, which extend ciliary tips to ciliary pore and directly release EVs into the environment.6,9 Males release EVs in a mechanically stimulated manner, regulate EV cargo content in response to mating partners, and deposit PKD-2::GFP-labeled EVs on the vulval cuticle of hermaphrodites during mating.9,10 Combined, our findings suggest that ciliary EV release is a dynamic process. Herein, we identify mechanisms controlling dynamic EV shedding using time-lapse imaging. Cilia can sustain the release of PKD-2-labeled EVs for 2 h. This extended release doesn't require neuronal transmission. Instead, ciliary intrinsic mechanisms regulate PKD-2 ciliary membrane replenishment and dynamic EV release. The kinesin-3 motor kinesin-like protein 6 (KLP-6) is necessary for initial and extended EV release, while the transition zone protein NPHP-4 is required only for sustained EV release. The dynamic replenishment of PKD-2 at the ciliary tip is key to sustained EV release. Our study provides a comprehensive portrait of real-time ciliary EV release and mechanisms supporting cilia as proficient EV release platforms.
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Affiliation(s)
- Juan Wang
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA.
| | - Josh Saul
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Inna A Nikonorova
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Carlos Nava Cruz
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Kaiden M Power
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Ken C Nguyen
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - David H Hall
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Maureen M Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA.
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2
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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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3
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McKenna ED, Sarbanes SL, Cummings SW, Roll-Mecak A. The Tubulin Code, from Molecules to Health and Disease. Annu Rev Cell Dev Biol 2023; 39:331-361. [PMID: 37843925 DOI: 10.1146/annurev-cellbio-030123-032748] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
Microtubules are essential dynamic polymers composed of α/β-tubulin heterodimers. They support intracellular trafficking, cell division, cellular motility, and other essential cellular processes. In many species, both α-tubulin and β-tubulin are encoded by multiple genes with distinct expression profiles and functionality. Microtubules are further diversified through abundant posttranslational modifications, which are added and removed by a suite of enzymes to form complex, stereotyped cellular arrays. The genetic and chemical diversity of tubulin constitute a tubulin code that regulates intrinsic microtubule properties and is read by cellular effectors, such as molecular motors and microtubule-associated proteins, to provide spatial and temporal specificity to microtubules in cells. In this review, we synthesize the rapidly expanding tubulin code literature and highlight limitations and opportunities for the field. As complex microtubule arrays underlie essential physiological processes, a better understanding of how cells employ the tubulin code has important implications for human disease ranging from cancer to neurological disorders.
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Affiliation(s)
- Elizabeth D McKenna
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA;
| | - Stephanie L Sarbanes
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA;
| | - Steven W Cummings
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA;
| | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA;
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland, USA
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4
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Chen J, Roll-Mecak A. Glutamylation is a negative regulator of microtubule growth. Mol Biol Cell 2023; 34:ar70. [PMID: 37074962 PMCID: PMC10295482 DOI: 10.1091/mbc.e23-01-0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 04/20/2023] Open
Abstract
Microtubules are noncovalent polymers built from αβ-tubulin dimers. The disordered C-terminal tubulin tails are functionalized with multiple glutamate chains of variable lengths added and removed by tubulin tyrosine ligases (TTLLs) and carboxypeptidases (CCPs). Glutamylation is abundant on stable microtubule arrays such as in axonemes and axons, and its dysregulation leads to human pathologies. Despite this, the effects of glutamylation on intrinsic microtubule dynamics are unclear. Here we generate tubulin with short and long glutamate chains and show that glutamylation slows the rate of microtubule growth and increases catastrophes as a function of glutamylation levels. This implies that the higher stability of glutamylated microtubules in cells is due to effectors. Interestingly, EB1 is minimally affected by glutamylation and thus can report on the growth rates of both unmodified and glutamylated microtubules. Finally, we show that glutamate removal by CCP1 and 5 is synergistic and occurs preferentially on soluble tubulin, unlike TTLL enzymes that prefer microtubules. This substrate preference establishes an asymmetry whereby once the microtubule depolymerizes, the released tubulin is reset to a less-modified state, while polymerized tubulin accumulates the glutamylation mark. Our work shows that a modification on the disordered tubulin tails can directly affect microtubule dynamics and furthers our understanding of the mechanistic underpinnings of the tubulin code.
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Affiliation(s)
- Jiayi Chen
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, and
| | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, and
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, Bethesda, MD 20892
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5
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O'Hagan R, Avrutis A, Ramicevic E. Functions of the tubulin code in the C. elegans nervous system. Mol Cell Neurosci 2022; 123:103790. [PMID: 36368428 DOI: 10.1016/j.mcn.2022.103790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/27/2022] [Accepted: 11/03/2022] [Indexed: 11/11/2022] Open
Abstract
Due to their elongated and polarized morphology, neurons rely on the microtubule (MT) cytoskeleton for their shape, as well as for efficient intracellular transport that maintains neuronal function, survival, and connectivity. Although all MTs are constructed from α- and β-tubulins that are highly conserved throughout eukaryotes, different MT networks within neurons exhibit different dynamics and functions. For example, molecular motors must be able to differentially recognize the axonal and dendritic MTs to deliver appropriate cargos to sensory endings and synaptic regions. The Tubulin Code hypothesis proposes that MTs can be specialized in form and function by chemical differences in their composition by inclusion of different α- and β-tubulins into the MT lattice, as well as differences in post-translational enzymatic modifications. The chemical differences encode information that allow MTs to regulate interactions with various microtubule-based molecular motors such as kinesins and dyneins as well as with structural microtubule-associated proteins (MAPs), which can, in turn, modify the function or stability of MTs. Here, we review studies involving C. elegans, a model organism with a relatively simple nervous system that is amenable to genetic analysis, that have contributed to our understanding of how the Tubulin Code can specialize neuronal MT networks to establish differences in neuronal morphology and function. Such studies have revealed molecules and mechanisms that are conserved in vertebrates and have the potential to inform our understanding of neurological diseases involving defects in the cytoskeleton and intracellular transport.
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Affiliation(s)
- Robert O'Hagan
- formerly at Biology Dept., Montclair State University, Montclair, NJ 07043, United States of America.
| | - Alexandra Avrutis
- formerly at Biology Dept., Montclair State University, Montclair, NJ 07043, United States of America
| | - Ema Ramicevic
- formerly at Biology Dept., Montclair State University, Montclair, NJ 07043, United States of America
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6
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Mechanisms of Regulation in Intraflagellar Transport. Cells 2022; 11:cells11172737. [PMID: 36078145 PMCID: PMC9454703 DOI: 10.3390/cells11172737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 08/30/2022] [Accepted: 08/31/2022] [Indexed: 11/30/2022] Open
Abstract
Cilia are eukaryotic organelles essential for movement, signaling or sensing. Primary cilia act as antennae to sense a cell’s environment and are involved in a wide range of signaling pathways essential for development. Motile cilia drive cell locomotion or liquid flow around the cell. Proper functioning of both types of cilia requires a highly orchestrated bi-directional transport system, intraflagellar transport (IFT), which is driven by motor proteins, kinesin-2 and IFT dynein. In this review, we explore how IFT is regulated in cilia, focusing from three different perspectives on the issue. First, we reflect on how the motor track, the microtubule-based axoneme, affects IFT. Second, we focus on the motor proteins, considering the role motor action, cooperation and motor-train interaction plays in the regulation of IFT. Third, we discuss the role of kinases in the regulation of the motor proteins. Our goal is to provide mechanistic insights in IFT regulation in cilia and to suggest directions of future research.
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7
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Protocol for determining the average speed and frequency of kinesin and dynein-driven intraflagellar transport (IFT) in C. elegans. STAR Protoc 2022; 3:101498. [PMID: 35776634 PMCID: PMC9250072 DOI: 10.1016/j.xpro.2022.101498] [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: 03/31/2022] [Revised: 05/03/2022] [Accepted: 06/07/2022] [Indexed: 12/03/2022] Open
Abstract
Here, we present a protocol to image a fluorescent-labeled intraflagellar transport (IFT) component in Caenorhabditis elegans with fluorescence microscopy, including steps of sample preparations, in vivo live-cell imaging, and post-microscopy analysis with kymographs. This protocol breaks down all processes into three categories: (1) pre-imaging preparations, (2) preparations for the time of image acquisition, and (3) post-imaging analyses. The protocol can be applied to determine the speed and frequency of moving particles. For complete details on the use and execution of this protocol, please refer to Cevik et al. (2021). In vivo time-lapse videos followed by kymograph analysis Kymograph-based analysis can reveal the speed and frequency of IFT C. elegans immobilization enables collecting high-quality time-lapse movies Quantify the IFT speed and frequency by synchronizing animals
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
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8
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O'Hagan R, Topalidou I. Fixation and Immunostaining of Endogenous Proteins or Post-translational Modificationsin Caenorhabditis elegans. Bio Protoc 2021; 11:e4172. [PMID: 34722819 DOI: 10.21769/bioprotoc.4172] [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: 03/10/2021] [Revised: 06/10/2021] [Accepted: 06/16/2021] [Indexed: 11/02/2022] Open
Abstract
Although the advent of genetically-encoded fluorescent markers, such as the green fluorescent protein (GFP; Chalfie et al., 1994 ), has enabled convenient visualization of gene expression in vivo, this method is generally not effective for detecting post-translational modifications because they are not translated from DNA sequences. Genetically-encoded, fluorescently-tagged transgene products can also be misleading for observing expression patterns because transgenes may lack endogenous regulatory DNA elements needed for precise regulation of expression that could result in over or under expression. Fluorescently-tagged proteins created by CRISPR genome editing are less prone to defective expression patterns because the loci retain endogenous DNA elements that regulate their transcription (Nance and Frøkjær-Jensen, 2019). However, even CRISPR alleles encoding heritable fluorescently-tagged protein markers can result in defects in function or localization of the gene product if the fluorescent tag obstructs or otherwise interferes with important protein interaction domains or affects the protein structure. Indirect immunofluorescence is a method for detecting endogenous gene expression or post-translational modifications without the need for transgenesis or genome editing. Here, we present a reliable protocol in which C. elegans nematodes are fixed, preserved, and permeabilized for staining with a primary antibody to bind proteins or post-translational modifications, which are then labeled with a secondary antibody conjugated to a fluorescent dye. Use of this method may be limited by the availability of (or ability to generate) a primary antibody that binds the epitope of interest in fixed animals. Thousands of animals are simultaneously subjected to a series of chemical treatments and washes in a single centrifuge tube, allowing large numbers of identically-treated stained animals to be examined. We have successfully used this protocol (O' Hagan et al., 2011 and 2017; Power et al., 2020 ) to preserve and detect post-translational modifications of tubulin in C. elegans ciliated sensory neurons and to detect non-modified endogenous protein (Topalidou and Chalfie, 2011).
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Affiliation(s)
- Robert O'Hagan
- Biology Department, Montclair State University, Montclair, USA
| | - Irini Topalidou
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
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9
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Moroz LL, Nikitin MA, Poličar PG, Kohn AB, Romanova DY. Evolution of glutamatergic signaling and synapses. Neuropharmacology 2021; 199:108740. [PMID: 34343611 DOI: 10.1016/j.neuropharm.2021.108740] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/13/2022]
Abstract
Glutamate (Glu) is the primary excitatory transmitter in the mammalian brain. But, we know little about the evolutionary history of this adaptation, including the selection of l-glutamate as a signaling molecule in the first place. Here, we used comparative metabolomics and genomic data to reconstruct the genealogy of glutamatergic signaling. The origin of Glu-mediated communications might be traced to primordial nitrogen and carbon metabolic pathways. The versatile chemistry of L-Glu placed this molecule at the crossroad of cellular biochemistry as one of the most abundant metabolites. From there, innovations multiplied. Many stress factors or injuries could increase extracellular glutamate concentration, which led to the development of modular molecular systems for its rapid sensing in bacteria and archaea. More than 20 evolutionarily distinct families of ionotropic glutamate receptors (iGluRs) have been identified in eukaryotes. The domain compositions of iGluRs correlate with the origins of multicellularity in eukaryotes. Although L-Glu was recruited as a neuro-muscular transmitter in the early-branching metazoans, it was predominantly a non-neuronal messenger, with a possibility that glutamatergic synapses evolved more than once. Furthermore, the molecular secretory complexity of glutamatergic synapses in invertebrates (e.g., Aplysia) can exceed their vertebrate counterparts. Comparative genomics also revealed 15+ subfamilies of iGluRs across Metazoa. However, most of this ancestral diversity had been lost in the vertebrate lineage, preserving AMPA, Kainate, Delta, and NMDA receptors. The widespread expansion of glutamate synapses in the cortical areas might be associated with the enhanced metabolic demands of the complex brain and compartmentalization of Glu signaling within modular neuronal ensembles.
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Affiliation(s)
- Leonid L Moroz
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, 32080, USA; Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
| | - Mikhail A Nikitin
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119991, Russia; Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, 127994, Russia
| | - Pavlin G Poličar
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, 32080, USA; Faculty of Computer and Information Science, University of Ljubljana, SI-1000, Ljubljana, Slovenia
| | - Andrea B Kohn
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, 32080, USA
| | - Daria Y Romanova
- Cellular Neurobiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Moscow, 117485, Russia.
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10
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Wang W, Jack BM, Wang HH, Kavanaugh MA, Maser RL, Tran PV. Intraflagellar Transport Proteins as Regulators of Primary Cilia Length. Front Cell Dev Biol 2021; 9:661350. [PMID: 34095126 PMCID: PMC8170031 DOI: 10.3389/fcell.2021.661350] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/06/2021] [Indexed: 12/21/2022] Open
Abstract
Primary cilia are small, antenna-like organelles that detect and transduce chemical and mechanical cues in the extracellular environment, regulating cell behavior and, in turn, tissue development and homeostasis. Primary cilia are assembled via intraflagellar transport (IFT), which traffics protein cargo bidirectionally along a microtubular axoneme. Ranging from 1 to 10 μm long, these organelles typically reach a characteristic length dependent on cell type, likely for optimum fulfillment of their specific roles. The importance of an optimal cilia length is underscored by the findings that perturbation of cilia length can be observed in a number of cilia-related diseases. Thus, elucidating mechanisms of cilia length regulation is important for understanding the pathobiology of ciliary diseases. Since cilia assembly/disassembly regulate cilia length, we review the roles of IFT in processes that affect cilia assembly/disassembly, including ciliary transport of structural and membrane proteins, ectocytosis, and tubulin posttranslational modification. Additionally, since the environment of a cell influences cilia length, we also review the various stimuli encountered by renal epithelia in healthy and diseased states that alter cilia length and IFT.
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Affiliation(s)
- Wei Wang
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Brittany M Jack
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Henry H Wang
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Matthew A Kavanaugh
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Robin L Maser
- Department of Clinical Laboratory Sciences, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Pamela V Tran
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
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11
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Akella JS, Barr MM. The tubulin code specializes neuronal cilia for extracellular vesicle release. Dev Neurobiol 2021; 81:231-252. [PMID: 33068333 PMCID: PMC8052387 DOI: 10.1002/dneu.22787] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 09/07/2020] [Accepted: 09/23/2020] [Indexed: 12/17/2022]
Abstract
Cilia are microtubule-based organelles that display diversity in morphology, ultrastructure, protein composition, and function. The ciliary microtubules of C. elegans sensory neurons exemplify this diversity and provide a paradigm to understand mechanisms driving ciliary specialization. Only a subset of ciliated neurons in C. elegans are specialized to make and release bioactive extracellular vesicles (EVs) into the environment. The cilia of extracellular vesicle releasing neurons have distinct axonemal features and specialized intraflagellar transport that are important for releasing EVs. In this review, we discuss the role of the tubulin code in the specialization of microtubules in cilia of EV releasing neurons.
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Affiliation(s)
- Jyothi S Akella
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Maureen M Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
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12
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Yang WT, Hong SR, He K, Ling K, Shaiv K, Hu J, Lin YC. The Emerging Roles of Axonemal Glutamylation in Regulation of Cilia Architecture and Functions. Front Cell Dev Biol 2021; 9:622302. [PMID: 33748109 PMCID: PMC7970040 DOI: 10.3389/fcell.2021.622302] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 02/11/2021] [Indexed: 12/14/2022] Open
Abstract
Cilia, which either generate coordinated motion or sense environmental cues and transmit corresponding signals to the cell body, are highly conserved hair-like structures that protrude from the cell surface among diverse species. Disruption of ciliary functions leads to numerous human disorders, collectively referred to as ciliopathies. Cilia are mechanically supported by axonemes, which are composed of microtubule doublets. It has been recognized for several decades that tubulins in axonemes undergo glutamylation, a post-translational polymodification, that conjugates glutamic acid chains onto the C-terminal tail of tubulins. However, the physiological roles of axonemal glutamylation were not uncovered until recently. This review will focus on how cells modulate glutamylation on ciliary axonemes and how axonemal glutamylation regulates cilia architecture and functions, as well as its physiological importance in human health. We will also discuss the conventional and emerging new strategies used to manipulate glutamylation in cilia.
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Affiliation(s)
- Wen-Ting Yang
- Institute of Molecular Medicine, National Tsing Hua University, HsinChu City, Taiwan
| | - Shi-Rong Hong
- Institute of Molecular Medicine, National Tsing Hua University, HsinChu City, Taiwan
| | - Kai He
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States
| | - Kun Ling
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States
| | - Kritika Shaiv
- Institute of Molecular Medicine, National Tsing Hua University, HsinChu City, Taiwan
| | - JingHua Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States
- Mayo Clinic Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, United States
| | - Yu-Chun Lin
- Institute of Molecular Medicine, National Tsing Hua University, HsinChu City, Taiwan
- Department of Medical Science, National Tsing Hua University, HsinChu City, Taiwan
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13
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Avcilar-Kucukgoze I, Kashina A. Hijacking tRNAs From Translation: Regulatory Functions of tRNAs in Mammalian Cell Physiology. Front Mol Biosci 2020; 7:610617. [PMID: 33392265 PMCID: PMC7773854 DOI: 10.3389/fmolb.2020.610617] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 11/10/2020] [Indexed: 12/12/2022] Open
Abstract
Transfer tRNAs (tRNAs) are small non-coding RNAs that are highly conserved in all kingdoms of life. Originally discovered as the molecules that deliver amino acids to the growing polypeptide chain during protein synthesis, tRNAs have been believed for a long time to play exclusive role in translation. However, recent studies have identified key roles for tRNAs and tRNA-derived small RNAs in multiple other processes, including regulation of transcription and translation, posttranslational modifications, stress response, and disease. These emerging roles suggest that tRNAs may be central players in the complex machinery of biological regulatory pathways. Here we overview these non-canonical roles of tRNA in normal physiology and disease, focusing largely on eukaryotic and mammalian systems.
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Affiliation(s)
- Irem Avcilar-Kucukgoze
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Anna Kashina
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States
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14
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Power KM, Akella JS, Gu A, Walsh JD, Bellotti S, Morash M, Zhang W, Ramadan YH, Ross N, Golden A, Smith HE, Barr MM, O’Hagan R. Mutation of NEKL-4/NEK10 and TTLL genes suppress neuronal ciliary degeneration caused by loss of CCPP-1 deglutamylase function. PLoS Genet 2020; 16:e1009052. [PMID: 33064774 PMCID: PMC7592914 DOI: 10.1371/journal.pgen.1009052] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 10/28/2020] [Accepted: 08/14/2020] [Indexed: 12/29/2022] Open
Abstract
Ciliary microtubules are subject to post-translational modifications that act as a "Tubulin Code" to regulate motor traffic, binding proteins and stability. In humans, loss of CCP1, a cytosolic carboxypeptidase and tubulin deglutamylating enzyme, causes infantile-onset neurodegeneration. In C. elegans, mutations in ccpp-1, the homolog of CCP1, result in progressive degeneration of neuronal cilia and loss of neuronal function. To identify genes that regulate microtubule glutamylation and ciliary integrity, we performed a forward genetic screen for suppressors of ciliary degeneration in ccpp-1 mutants. We isolated the ttll-5(my38) suppressor, a mutation in a tubulin tyrosine ligase-like glutamylase gene. We show that mutation in the ttll-4, ttll-5, or ttll-11 gene suppressed the hyperglutamylation-induced loss of ciliary dye filling and kinesin-2 mislocalization in ccpp-1 cilia. We also identified the nekl-4(my31) suppressor, an allele affecting the NIMA (Never in Mitosis A)-related kinase NEKL-4/NEK10. In humans, NEK10 mutation causes bronchiectasis, an airway and mucociliary transport disorder caused by defective motile cilia. C. elegans NEKL-4 localizes to the ciliary base but does not localize to cilia, suggesting an indirect role in ciliary processes. This work defines a pathway in which glutamylation, a component of the Tubulin Code, is written by TTLL-4, TTLL-5, and TTLL-11; is erased by CCPP-1; is read by ciliary kinesins; and its downstream effects are modulated by NEKL-4 activity. Identification of regulators of microtubule glutamylation in diverse cellular contexts is important to the development of effective therapies for disorders characterized by changes in microtubule glutamylation. By identifying C. elegans genes important for neuronal and ciliary stability, our work may inform research into the roles of the tubulin code in human ciliopathies and neurodegenerative diseases.
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Affiliation(s)
- Kade M. Power
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Jyothi S. Akella
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Amanda Gu
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Jonathon D. Walsh
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Sebastian Bellotti
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Margaret Morash
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Winnie Zhang
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Yasmin H. Ramadan
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Nicole Ross
- Biology Department, Montclair State University, Montclair, NJ, United States of America
| | - Andy Golden
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Harold E. Smith
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Maureen M. Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Robert O’Hagan
- Biology Department, Montclair State University, Montclair, NJ, United States of America
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15
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Asih PR, Prikas E, Stefanoska K, Tan ARP, Ahel HI, Ittner A. Functions of p38 MAP Kinases in the Central Nervous System. Front Mol Neurosci 2020; 13:570586. [PMID: 33013322 PMCID: PMC7509416 DOI: 10.3389/fnmol.2020.570586] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/18/2020] [Indexed: 12/22/2022] Open
Abstract
Mitogen-activated protein (MAP) kinases are a central component in signaling networks in a multitude of mammalian cell types. This review covers recent advances on specific functions of p38 MAP kinases in cells of the central nervous system. Unique and specific functions of the four mammalian p38 kinases are found in all major cell types in the brain. Mechanisms of p38 activation and downstream phosphorylation substrates in these different contexts are outlined and how they contribute to functions of p38 in physiological and under disease conditions. Results in different model organisms demonstrated that p38 kinases are involved in cognitive functions, including functions related to anxiety, addiction behavior, neurotoxicity, neurodegeneration, and decision making. Finally, the role of p38 kinases in psychiatric and neurological conditions and the current progress on therapeutic inhibitors targeting p38 kinases are covered and implicate p38 kinases in a multitude of CNS-related physiological and disease states.
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Affiliation(s)
- Prita R Asih
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Emmanuel Prikas
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Kristie Stefanoska
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Amanda R P Tan
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Holly I Ahel
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Arne Ittner
- Dementia Research Centre, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
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16
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Bodakuntla S, Magiera MM, Janke C. Measuring the Impact of Tubulin Posttranslational Modifications on Axonal Transport. Methods Mol Biol 2020; 2101:353-370. [PMID: 31879913 DOI: 10.1007/978-1-0716-0219-5_20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Axonal transport is a process essential for neuronal function and survival that takes place on the cellular highways-the microtubules. It requires three major components: the microtubules that serve as tracks for the transport, the motor proteins that drive the movement, and the transported cargoes with their adaptor proteins. Axonal transport could be controlled by tubulin posttranslational modifications, which by decorating specific microtubule tracks could determine the specificity of cargo delivery inside neurons. However, it appears that the effects of tubulin modifications on transport can be rather subtle, and might thus be easily overlooked depending on which parameter of the transport process is analyzed. Here we propose an analysis paradigm that allows detecting rather subtle alterations in neuronal transport, as induced for instance by accumulation of posttranslational polyglutamylation. Analyzing mitochondria movements in axons, we found that neither the average speed nor the distance traveled were affected by hyperglutamylation, but we detected an about 50% reduction of the overall motility, suggesting that polyglutamylation controls the efficiency of mitochondria transport in axons. Our protocol can readily be expanded to the analysis of the impact of other tubulin modifications on the transport of a range of different neuronal cargoes.
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Affiliation(s)
- Satish Bodakuntla
- Institut Curie, PSL Research University, CNRS UMR3348, Centre Universitaire, Orsay, France.,Université Paris Sud, Université Paris-Saclay, CNRS UMR3348, Orsay, France
| | - Maria M Magiera
- Institut Curie, PSL Research University, CNRS UMR3348, Centre Universitaire, Orsay, France. .,Université Paris Sud, Université Paris-Saclay, CNRS UMR3348, Orsay, France.
| | - Carsten Janke
- Institut Curie, PSL Research University, CNRS UMR3348, Centre Universitaire, Orsay, France. .,Université Paris Sud, Université Paris-Saclay, CNRS UMR3348, Orsay, France.
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