51
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Reilly ML, Benmerah A. Ciliary kinesins beyond IFT: Cilium length, disassembly, cargo transport and signalling. Biol Cell 2019; 111:79-94. [PMID: 30720881 DOI: 10.1111/boc.201800074] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/18/2019] [Indexed: 02/06/2023]
Abstract
Cilia and flagella are microtubule-based antenna which are highly conserved among eukaryotes. In vertebrates, primary and motile cilia have evolved to exert several key functions during development and tissue homoeostasis. Ciliary dysfunction in humans causes a highly heterogeneous group of diseases called ciliopathies, a class of genetic multisystemic disorders primarily affecting kidney, skeleton, retina, lung and the central nervous system. Among key ciliary proteins, kinesin family members (KIF) are microtubule-interacting proteins involved in many diverse cellular functions, including transport of cargo (organelles, proteins and lipids) along microtubules and regulating the dynamics of cytoplasmic and spindle microtubules through their depolymerising activity. Many KIFs are also involved in diverse ciliary functions including assembly/disassembly, motility and signalling. We here review these ciliary kinesins in vertebrates and focus on their involvement in ciliopathy-related disorders.
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Affiliation(s)
- Madeline Louise Reilly
- Laboratory of Hereditary Kidney Diseases, INSERM UMR 1163, Paris Descartes University, Imagine Institute, Paris, 75015, France.,Paris Diderot University, Paris, 75013, France
| | - Alexandre Benmerah
- Laboratory of Hereditary Kidney Diseases, INSERM UMR 1163, Paris Descartes University, Imagine Institute, Paris, 75015, France
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52
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Insinna C, Lu Q, Teixeira I, Harned A, Semler EM, Stauffer J, Magidson V, Tiwari A, Kenworthy AK, Narayan K, Westlake CJ. Investigation of F-BAR domain PACSIN proteins uncovers membrane tubulation function in cilia assembly and transport. Nat Commun 2019; 10:428. [PMID: 30683896 PMCID: PMC6347608 DOI: 10.1038/s41467-018-08192-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 12/20/2018] [Indexed: 12/03/2022] Open
Abstract
The intracellular ciliogenesis pathway requires membrane trafficking, fusion, and reorganization. Here, we demonstrate in human cells and zebrafish that the F-BAR domain containing proteins PACSIN1 and -2 play an essential role in ciliogenesis, similar to their binding partner and membrane reorganizer EHD1. In mature cilia, PACSINs and EHDs are dynamically localized to the ciliary pocket membrane (CPM) and transported away from this structure on membrane tubules along with proteins that exit the cilium. PACSINs function early in ciliogenesis at the ciliary vesicle (CV) stage to promote mother centriole to basal body transition. Remarkably, we show that PACSIN1 and EHD1 assemble membrane t7ubules from the developing intracellular cilium that attach to the plasma membrane, creating an extracellular membrane channel (EMC) to the outside of the cell. Together, our work uncovers a function for F-BAR proteins and membrane tubulation in ciliogenesis and explains how the intracellular cilium emerges from the cell.
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Affiliation(s)
- Christine Insinna
- Laboratory of Cellular and Developmental Signaling, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Quanlong Lu
- Laboratory of Cellular and Developmental Signaling, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Isabella Teixeira
- Laboratory of Cellular and Developmental Signaling, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Adam Harned
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21701, USA
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Elizabeth M Semler
- Laboratory of Cellular and Developmental Signaling, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Jim Stauffer
- Laboratory of Cellular and Developmental Signaling, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Valentin Magidson
- Laboratory of Cellular and Developmental Signaling, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Ajit Tiwari
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Anne K Kenworthy
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Kedar Narayan
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21701, USA
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Christopher J Westlake
- Laboratory of Cellular and Developmental Signaling, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA.
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53
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Han KJ, Wu Z, Pearson CG, Peng J, Song K, Liu CW. Deubiquitylase USP9X maintains centriolar satellite integrity by stabilizing pericentriolar material 1 protein. J Cell Sci 2019; 132:jcs.221663. [PMID: 30584065 DOI: 10.1242/jcs.221663] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 12/19/2018] [Indexed: 12/12/2022] Open
Abstract
Centriolar satellites are small cytoplasmic granules that play important roles in regulating the formation of centrosomes and primary cilia. Ubiquitylation of satellite proteins, including the core satellite scaffold protein pericentriolar material 1 (PCM1), regulates centriolar satellite integrity. Currently, deubiquitylases that control centriolar satellite integrity have not been identified. In this study, we find that the deubiquitylase USP9X binds PCM1, and antagonizes PCM1 ubiquitylation to protect it from proteasomal degradation. Knockdown of USP9X in human cell lines reduces PCM1 protein levels, disrupts centriolar satellite particles and causes localization of satellite proteins, such as CEP290, to centrosomes. Interestingly, knockdown of mindbomb 1 (MIB1), a ubiquitin ligase that promotes PCM1 ubiquitylation and degradation, in USP9X-depleted cells largely restores PCM1 protein levels and corrects defects caused by the loss of USP9X. Overall, our study reveals that USP9X is a constituent of centriolar satellites and functions to maintain centriolar satellite integrity by stabilizing PCM1.
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Affiliation(s)
- Ke-Jun Han
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Zhiping Wu
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Chad G Pearson
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Junmin Peng
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Kunhua Song
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Chang-Wei Liu
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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54
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Nishimura Y, Kasahara K, Shiromizu T, Watanabe M, Inagaki M. Primary Cilia as Signaling Hubs in Health and Disease. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1801138. [PMID: 30643718 PMCID: PMC6325590 DOI: 10.1002/advs.201801138] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/20/2018] [Indexed: 05/13/2023]
Abstract
Primary cilia detect extracellular cues and transduce these signals into cells to regulate proliferation, migration, and differentiation. Here, the function of primary cilia as signaling hubs of growth factors and morphogens is in focus. First, the molecular mechanisms regulating the assembly and disassembly of primary cilia are described. Then, the role of primary cilia in mediating growth factor and morphogen signaling to maintain human health and the potential mechanisms by which defects in these pathways contribute to human diseases, such as ciliopathy, obesity, and cancer are described. Furthermore, a novel signaling pathway by which certain growth factors stimulate cell proliferation through suppression of ciliogenesis is also described, suggesting novel therapeutic targets in cancer.
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Affiliation(s)
- Yuhei Nishimura
- Department of Integrative PharmacologyMie University Graduate School of MedicineTsuMie514‐8507Japan
| | - Kousuke Kasahara
- Department of PhysiologyMie University Graduate School of MedicineTsuMie514‐8507Japan
| | - Takashi Shiromizu
- Department of Integrative PharmacologyMie University Graduate School of MedicineTsuMie514‐8507Japan
| | - Masatoshi Watanabe
- Department of Oncologic PathologyMie University Graduate School of MedicineTsuMie514‐8507Japan
| | - Masaki Inagaki
- Department of PhysiologyMie University Graduate School of MedicineTsuMie514‐8507Japan
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55
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Endosomal trafficking defects in patient cells with KIAA1109 biallelic variants. Genes Dis 2019; 6:56-67. [PMID: 30906834 PMCID: PMC6411657 DOI: 10.1016/j.gendis.2018.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 12/27/2018] [Indexed: 02/06/2023] Open
Abstract
The uncharacterized gene KIAA1 109 has recently been associated with a congenital neurological malformation disorder that variably presents with arthrogryposis, craniofacial and/or cardiac abnormalities. We have identified two additional patients with compound heterozygous KIAA1109 variants presenting with the same neurological malformations. The mechanism whereby KIAA1109 loss of function causes this spectrum of disorders was the primary focus of our studies. We hypothesized that KIAA1109 function could be conserved relative to the fly gene tweek and examined endocytosis and endosome recycling in patient fibroblasts. Furthermore, we examined the structure of the cytoskeleton and cilia based on functional overlap with endocytosis and several known etiologies for neuronal migration disorders. Utilizing primary dermal fibroblasts from one patient and a healthy donor, we performed immunofluorescence and endocytosis assays to examine the endosomal, cytoskeletal, and ciliary cellular phenotypes. We found notable abnormalities in endosomal trafficking and endosome recycling pathways. We also observed changes in the actin cytoskeleton and cilia structural dynamics. We conclude that the function of KIAA1109 in humans may indeed overlap with the function of the Drosophila ortholog, resulting in perturbations to endosomal trafficking and the actin cytoskeleton. These alterations have ripple effects, altering many pathways that are critical for proper neuronal migration and embryonic development.
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56
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Hinze C, Boucrot E. Endocytosis in proliferating, quiescent and terminally differentiated cells. J Cell Sci 2018; 131:131/23/jcs216804. [PMID: 30504135 DOI: 10.1242/jcs.216804] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Endocytosis mediates nutrient uptake, receptor internalization and the regulation of cell signaling. It is also hijacked by many bacteria, viruses and toxins to mediate their cellular entry. Several endocytic routes exist in parallel, fulfilling different functions. Most studies on endocytosis have used transformed cells in culture. However, as the majority of cells in an adult body have exited the cell cycle, our understanding is biased towards proliferating cells. Here, we review the evidence for the different pathways of endocytosis not only in dividing, but also in quiescent, senescent and terminally differentiated cells. During mitosis, residual endocytosis is dedicated to the internalization of caveolae and specific receptors. In non-dividing cells, clathrin-mediated endocytosis (CME) functions, but the activity of alternative processes, such as caveolae, macropinocytosis and clathrin-independent routes, vary widely depending on cell types and functions. Endocytosis supports the quiescent state by either upregulating cell cycle arrest pathways or downregulating mitogen-induced signaling, thereby inhibiting cell proliferation. Endocytosis in terminally differentiated cells, such as skeletal muscles, adipocytes, kidney podocytes and neurons, supports tissue-specific functions. Finally, uptake is downregulated in senescent cells, making them insensitive to proliferative stimuli by growth factors. Future studies should reveal the molecular basis for the differences in activities between the different cell states.
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Affiliation(s)
- Claudia Hinze
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK
| | - Emmanuel Boucrot
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, UK .,Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, London WC1E 7HX, UK
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57
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Álvarez-Satta M, Matheu A. Primary cilium and glioblastoma. Ther Adv Med Oncol 2018; 10:1758835918801169. [PMID: 30302130 PMCID: PMC6170955 DOI: 10.1177/1758835918801169] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 08/20/2018] [Indexed: 01/14/2023] Open
Abstract
Glioblastoma (GBM) represents the most common, malignant and lethal primary brain tumour in adults. The primary cilium is a highly conserved and dynamic organelle that protrudes from the apical surface of virtually every type of mammalian cell. There is increasing evidence that abnormal cilia are involved in cancer progression, since primary cilia regulate cell cycle and signalling transduction. In this review, we summarize the role of primary cilium specifically with regard to GBM, where there is evidence postulating it as a critical mediator of GBM tumorigenesis and progression. This opens the way to the application of cilia-targeted therapies (‘ciliotherapy’) as a new approach in the fight against this devastating tumour.
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Affiliation(s)
- María Álvarez-Satta
- Cellular Oncology group, Biodonostia Health Research Institute, San Sebastian, Spain
| | - Ander Matheu
- Cellular Oncology group, Biodonostia Health Research Institute, Paseo Dr. Beguiristain s/n, CP 20014 San Sebastian, Spain CIBER de Fragilidad y Envejecimiento Saludable (CIBERfes), Madrid, Spain IKERBASQUE, Basque Foundation, Bilbao, Spain
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58
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Takeuchi Y, Kito A, Itoh S, Naruse H, Fujikawa J, Sadek KM, Akiyama S, Yamashiro T, Wakisaka S, Abe M. Kruppel-Like Factor 4 represses osteoblast differentiation via ciliary Hedgehog signaling. Exp Cell Res 2018; 371:417-425. [PMID: 30193838 DOI: 10.1016/j.yexcr.2018.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/14/2018] [Accepted: 09/03/2018] [Indexed: 10/28/2022]
Abstract
Primary cilia are appendages observed in most types of cells, and serve as cellular antennae for sensing environmental signals. Evidence is accumulating that correct ciliogenesis and ciliary functions are indispensable for normal skeletal development by regulating signaling pathways important for bone development. However, whether ciliogenesis is regulated by bone-related factors in osteoblasts is largely unknown. Here we show that Kruppel-Like Factor 4 (KLF4), which is known to repress osteoblast differentiation, supports the formation and maintenance of cilia in cultured osteoblasts; however, the length of the cilia observed in KLF4-induced cells were significantly shorter compared to the control cells. Basal Hedgehog signaling was repressed by KLF4. Significantly, activating Hedgehog signaling using a Smoothened agonist significantly rescued osteoblast mineralization and osteoblastic gene expressions. Global gene expression analysis showed that KLF4 induced number of genes including the nuclear receptor, Pregnane X receptor (PXR), and PXR repressed calvarial osteoblast mineralization and repressed Gli1 expression similar as the effect observed by inducing KLF4. Our results implicate that KLF4 plays important roles for maintaining osteoblasts in an immature state by repressing basal activation of the Hedgehog signaling.
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Affiliation(s)
- Yuto Takeuchi
- Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Osaka, Japan; Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Akiyoshi Kito
- Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Osaka, Japan; Osaka University Dental Hospital Division of Special Care Dentistry, Osaka, Japan
| | - Shousaku Itoh
- Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Haruna Naruse
- Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Junji Fujikawa
- Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Osaka, Japan; Osaka University Dental Hospital Division of Special Care Dentistry, Osaka, Japan
| | - Kadry Mahamed Sadek
- Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Osaka, Japan; Department of Biochemistry, Faculty of Veterinary Medicine, Damnhour University, Egypt
| | - Shigehisa Akiyama
- Osaka University Dental Hospital Division of Special Care Dentistry, Osaka, Japan
| | - Takashi Yamashiro
- Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Satoshi Wakisaka
- Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Makoto Abe
- Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Osaka, Japan.
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59
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Morthorst SK, Christensen ST, Pedersen LB. Regulation of ciliary membrane protein trafficking and signalling by kinesin motor proteins. FEBS J 2018; 285:4535-4564. [PMID: 29894023 DOI: 10.1111/febs.14583] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/09/2018] [Accepted: 06/11/2018] [Indexed: 12/14/2022]
Abstract
Primary cilia are antenna-like sensory organelles that regulate a substantial number of cellular signalling pathways in vertebrates, both during embryonic development as well as in adulthood, and mutations in genes coding for ciliary proteins are causative of an expanding group of pleiotropic diseases known as ciliopathies. Cilia consist of a microtubule-based axoneme core, which is subtended by a basal body and covered by a bilayer lipid membrane of unique protein and lipid composition. Cilia are dynamic organelles, and the ability of cells to regulate ciliary protein and lipid content in response to specific cellular and environmental cues is crucial for balancing ciliary signalling output. Here we discuss mechanisms involved in regulation of ciliary membrane protein trafficking and signalling, with main focus on kinesin-2 and kinesin-3 family members.
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60
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Liu H, Li W, Zhang Y, Zhang Z, Shang X, Zhang L, Zhang S, Li Y, Somoza AV, Delpi B, Gerton GL, Foster JA, Hess RA, Pazour GJ, Zhang Z. IFT25, an intraflagellar transporter protein dispensable for ciliogenesis in somatic cells, is essential for sperm flagella formation. Biol Reprod 2018; 96:993-1006. [PMID: 28430876 DOI: 10.1093/biolre/iox029] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 04/13/2017] [Indexed: 12/25/2022] Open
Abstract
Intraflagellar transport (IFT) is a conserved mechanism essential for the assembly and maintenance of most eukaryotic cilia and flagella. However, IFT25, a component of the IFT complex, is not required for the formation of cilia in somatic tissues. In mice, the gene is highly expressed in the testis, and its expression is upregulated during the final phase when sperm flagella are formed. To investigate the role of IFT25 in sperm flagella formation, the gene was specifically disrupted in male germ cells. All homozygous knockout mice survived to adulthood and did not show any gross abnormalities. However, all homozygous knockout males were completely infertile. Sperm numbers were reduced and these sperm were completely immotile. Multiple morphological abnormalities were observed in sperm, including round heads, short and bent tails, with some tails showing branched flagella and others with frequent abnormal thicknesses, as well as swollen tips of the tail. Transmission electron microscopy revealed that flagellar accessory structures, including the fibrous sheath and outer dense fibers, were disorganized, and most sperm had also lost the "9+2" microtubule structure. In the testis, IFT25 forms a complex with other IFT proteins. In Ift25 knockout testes, IFT27, an IFT25 binding partner, was missing, and IFT20 and IFT81 levels were also reduced. Our findings suggest that IFT25, although not necessary for the formation of cilia in somatic cells, is indispensable for sperm flagellum formation and male fertility in mice.
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Affiliation(s)
- Hong Liu
- School of Public Health and Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Wuhan University of Science and Technology, Wuhan, Hubei, China.,Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Wei Li
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Yong Zhang
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, USA.,Department of Dermatology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhengang Zhang
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, USA.,Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xuejun Shang
- Department of Andrology, Jinling Hospital, Nanjing University, School of Medicine, Nanjing, China
| | - Ling Zhang
- School of Public Health and Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Wuhan University of Science and Technology, Wuhan, Hubei, China.,Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Shiyang Zhang
- School of Public Health and Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Wuhan University of Science and Technology, Wuhan, Hubei, China.,Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Yanwei Li
- Department of Computer Science, Wellesley College, Wellesley, Massachusetts, USA
| | - Andres V Somoza
- Department of Humanities and Sciences, Honor College, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Brandon Delpi
- Department of Biology, Randolph-Macon College, Ashland, Virginia, USA
| | - George L Gerton
- Center for Research on Reproduction and Women's Health Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - James A Foster
- Department of Biology, Randolph-Macon College, Ashland, Virginia, USA
| | - Rex A Hess
- Comparative Biosciences, College of Veterinary Medicine, University of Illinois, Urbana, Illinois, USA
| | - Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Zhibing Zhang
- School of Public Health and Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Wuhan University of Science and Technology, Wuhan, Hubei, China.,Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, USA
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61
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Hua K, Ferland RJ. Primary cilia proteins: ciliary and extraciliary sites and functions. Cell Mol Life Sci 2018; 75:1521-1540. [PMID: 29305615 PMCID: PMC5899021 DOI: 10.1007/s00018-017-2740-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 12/21/2017] [Accepted: 12/27/2017] [Indexed: 02/07/2023]
Abstract
Primary cilia are immotile organelles known for their roles in development and cell signaling. Defects in primary cilia result in a range of disorders named ciliopathies. Because this organelle can be found singularly on almost all cell types, its importance extends to most organ systems. As such, elucidating the importance of the primary cilium has attracted researchers from all biological disciplines. As the primary cilia field expands, caution is warranted in attributing biological defects solely to the function of this organelle, since many of these "ciliary" proteins are found at other sites in cells and likely have non-ciliary functions. Indeed, many, if not all, cilia proteins have locations and functions outside the primary cilium. Extraciliary functions are known to include cell cycle regulation, cytoskeletal regulation, and trafficking. Cilia proteins have been observed in the nucleus, at the Golgi apparatus, and even in immune synapses of T cells (interestingly, a non-ciliated cell). Given the abundance of extraciliary sites and functions, it can be difficult to definitively attribute an observed phenotype solely to defective cilia rather than to some defective extraciliary function or a combination of both. Thus, extraciliary sites and functions of cilia proteins need to be considered, as well as experimentally determined. Through such consideration, we will understand the true role of the primary cilium in disease as compared to other cellular processes' influences in mediating disease (or through a combination of both). Here, we review a compilation of known extraciliary sites and functions of "cilia" proteins as a means to demonstrate the potential non-ciliary roles for these proteins.
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Affiliation(s)
- Kiet Hua
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, 47 New Scotland Avenue, MC-136, Albany, NY, 12208, USA.
| | - Russell J Ferland
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, 47 New Scotland Avenue, MC-136, Albany, NY, 12208, USA.
- Department of Neurology, Albany Medical College, Albany, NY, 12208, USA.
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62
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Taschner M, Lorentzen A, Mourão A, Collins T, Freke GM, Moulding D, Basquin J, Jenkins D, Lorentzen E. Crystal structure of intraflagellar transport protein 80 reveals a homo-dimer required for ciliogenesis. eLife 2018; 7:33067. [PMID: 29658880 PMCID: PMC5931796 DOI: 10.7554/elife.33067] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 04/13/2018] [Indexed: 12/16/2022] Open
Abstract
Oligomeric assemblies of intraflagellar transport (IFT) particles build cilia through sequential recruitment and transport of ciliary cargo proteins within cilia. Here we present the 1.8 Å resolution crystal structure of the Chlamydomonas IFT-B protein IFT80, which reveals the architecture of two N-terminal β-propellers followed by an α-helical extension. The N-terminal β-propeller tethers IFT80 to the IFT-B complex via IFT38 whereas the second β-propeller and the C-terminal α-helical extension result in IFT80 homo-dimerization. Using CRISPR/Cas to create biallelic Ift80 frameshift mutations in IMCD3 mouse cells, we demonstrate that IFT80 is absolutely required for ciliogenesis. Structural mapping and rescue experiments reveal that human disease-causing missense mutations do not cluster within IFT80 and form functional IFT particles. Unlike missense mutant forms of IFT80, deletion of the C-terminal dimerization domain prevented rescue of ciliogenesis. Taken together our results may provide a first insight into higher order IFT complex formation likely required for IFT train formation.
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Affiliation(s)
- Michael Taschner
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Anna Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - André Mourão
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Toby Collins
- Genetics and Genomic Medicine, University College London, London, United Kingdom
| | - Grace M Freke
- Genetics and Genomic Medicine, University College London, London, United Kingdom
| | - Dale Moulding
- Developmental Biology and Cancer Programmes, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Jerome Basquin
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Dagan Jenkins
- Genetics and Genomic Medicine, University College London, London, United Kingdom
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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63
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Scheidel N, Kennedy J, Blacque OE. Endosome maturation factors Rabenosyn-5/VPS45 and caveolin-1 regulate ciliary membrane and polycystin-2 homeostasis. EMBO J 2018; 37:embj.201798248. [PMID: 29572244 DOI: 10.15252/embj.201798248] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 02/08/2018] [Accepted: 02/16/2018] [Indexed: 12/24/2022] Open
Abstract
Primary cilium structure and function relies on control of ciliary membrane homeostasis, regulated by membrane trafficking processes that deliver and retrieve ciliary components at the periciliary membrane. However, the molecular mechanisms controlling ciliary membrane establishment and maintenance, especially in relation to endocytosis, remain poorly understood. Here, using Caenorhabditis elegans, we describe closely linked functions for early endosome (EE) maturation factors RABS-5 (Rabenosyn-5) and VPS-45 (VPS45) in regulating cilium length and morphology, ciliary and periciliary membrane volume, and ciliary signalling-related sensory behaviour. We demonstrate that RABS-5 and VPS-45 control periciliary vesicle number and levels of select EE/endocytic markers (WDFY-2, CAV-1) and the ciliopathy membrane receptor PKD-2 (polycystin-2). Moreover, we show that CAV-1 (caveolin-1) also controls PKD-2 ciliary levels and associated sensory behaviour. These data link RABS-5 and VPS-45 ciliary functions to the processing of periciliary-derived endocytic vesicles and regulation of ciliary membrane homeostasis. Our findings also provide insight into the regulation of PKD-2 ciliary levels via integrated endosomal sorting and CAV-1-mediated endocytosis.
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Affiliation(s)
- Noémie Scheidel
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin 4, Ireland
| | - Julie Kennedy
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin 4, Ireland
| | - Oliver E Blacque
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin 4, Ireland
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64
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Billot K, Coquil C, Villiers B, Josselin-Foll B, Desban N, Delehouzé C, Oumata N, Le Meur Y, Boletta A, Weimbs T, Grosch M, Witzgall R, Saunier S, Fischer E, Pontoglio M, Fautrel A, Mrug M, Wallace D, Tran PV, Trudel M, Bukanov N, Ibraghimov-Beskrovnaya O, Meijer L. Casein kinase 1ε and 1α as novel players in polycystic kidney disease and mechanistic targets for (R)-roscovitine and (S)-CR8. Am J Physiol Renal Physiol 2018. [PMID: 29537311 DOI: 10.1152/ajprenal.00489.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Following the discovery of (R)-roscovitine's beneficial effects in three polycystic kidney disease (PKD) mouse models, cyclin-dependent kinases (CDKs) inhibitors have been investigated as potential treatments. We have used various affinity chromatography approaches to identify the molecular targets of roscovitine and its more potent analog (S)-CR8 in human and murine polycystic kidneys. These methods revealed casein kinases 1 (CK1) as additional targets of the two drugs. CK1ε expression at the mRNA and protein levels is enhanced in polycystic kidneys of 11 different PKD mouse models as well as in human polycystic kidneys. A shift in the pattern of CK1α isoforms is observed in all PKD mouse models. Furthermore, the catalytic activities of both CK1ε and CK1α are increased in mouse polycystic kidneys. Inhibition of CK1ε and CK1α may thus contribute to the long-lasting attenuating effects of roscovitine and (S)-CR8 on cyst development. CDKs and CK1s may constitute a dual therapeutic target to develop kinase inhibitory PKD drug candidates.
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Affiliation(s)
- Katy Billot
- ManRos Therapeutics, Centre de Perharidy , Roscoff , France
| | | | | | - Béatrice Josselin-Foll
- CNRS "Protein Phosphorylation and Human Disease Group, Station Biologique, Roscoff Cedex, Bretagne , France
| | - Nathalie Desban
- CNRS "Protein Phosphorylation and Human Disease Group, Station Biologique, Roscoff Cedex, Bretagne , France
| | - Claire Delehouzé
- CNRS "Protein Phosphorylation and Human Disease Group, Station Biologique, Roscoff Cedex, Bretagne , France
| | - Nassima Oumata
- ManRos Therapeutics, Centre de Perharidy , Roscoff , France
| | - Yannick Le Meur
- Service de Néphrologie, Centre Hospitalier Universitaire La Cavale Blanche, Rue Tanguy Prigent, Brest Cedex, France
| | - Alessandra Boletta
- Division of Genetics and Cell Biology, DIBIT San Raffaele Scientific Institute , Milan , Italy
| | - Thomas Weimbs
- Department of Molecular, Cellular, and Developmental Biology, Neuroscience Research Institute, University of California Santa Barbara , Santa Barbara, California
| | - Melanie Grosch
- University of Regensburg, Institute for Molecular and Cellular Anatomy, Universitätsstr 31, Regensburg , Germany
| | - Ralph Witzgall
- University of Regensburg, Institute for Molecular and Cellular Anatomy, Universitätsstr 31, Regensburg , Germany
| | | | - Evelyne Fischer
- "Expression Génique, Développement et Maladies", Equipe 26/INSERM U1016/CNRS UMR 8104/Université Paris-Descartes, Institut Cochin, Département Génétique & Développement, Paris , France
| | - Marco Pontoglio
- "Expression Génique, Développement et Maladies", Equipe 26/INSERM U1016/CNRS UMR 8104/Université Paris-Descartes, Institut Cochin, Département Génétique & Développement, Paris , France
| | - Alain Fautrel
- Université de Rennes 1, H2P2 Histopathology Core Facility, Rennes Cedex, France
| | - Michal Mrug
- Division of Nephrology, University of Alabama at Birmingham , Birmingham, Alabama.,Department of Veterans Affairs Medical Center , Birmingham, Alabama
| | - Darren Wallace
- University of Kansas Medical Center, The Jared Grantham Kidney Institute , Kansas City, Kansas
| | - Pamela V Tran
- University of Kansas Medical Center, The Jared Grantham Kidney Institute , Kansas City, Kansas.,University of Kansas Medical Center, Department of Anatomy and Cell Biology , Kansas City, Kansas
| | - Marie Trudel
- Institut de Recherches Cliniques de Montréal, Molecular Genetics and Development, Montreal, Quebec , Canada
| | - Nikolay Bukanov
- Sanofi Genzyme, Rare Renal and Bone Diseases, Framingham, Massachusetts
| | | | - Laurent Meijer
- ManRos Therapeutics, Centre de Perharidy , Roscoff , France
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65
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Abstract
Cilia are microtubule-based organelles extending from a basal body at the surface of eukaryotic cells. Cilia regulate cell and fluid motility, sensation and developmental signaling, and ciliary defects cause human diseases (ciliopathies) affecting the formation and function of many tissues and organs. Over the past decade, various Rab and Rab-like membrane trafficking proteins have been shown to regulate cilia-related processes such as basal body maturation, ciliary axoneme extension, intraflagellar transport and ciliary signaling. In this review, we provide a comprehensive overview of Rab protein ciliary associations, drawing on findings from multiple model systems, including mammalian cell culture, mice, zebrafish, C. elegans, trypanosomes, and green algae. We also discuss several emerging mechanistic themes related to ciliary Rab cascades and functional redundancy.
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Affiliation(s)
- Oliver E Blacque
- a School of Biomolecular and Biomedical Science , University College Dublin , Belfield, Dublin , Ireland
| | - Noemie Scheidel
- a School of Biomolecular and Biomedical Science , University College Dublin , Belfield, Dublin , Ireland
| | - Stefanie Kuhns
- a School of Biomolecular and Biomedical Science , University College Dublin , Belfield, Dublin , Ireland
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66
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Vion AC, Alt S, Klaus-Bergmann A, Szymborska A, Zheng T, Perovic T, Hammoutene A, Oliveira MB, Bartels-Klein E, Hollfinger I, Rautou PE, Bernabeu MO, Gerhardt H. Primary cilia sensitize endothelial cells to BMP and prevent excessive vascular regression. J Cell Biol 2018; 217:1651-1665. [PMID: 29500191 PMCID: PMC5940299 DOI: 10.1083/jcb.201706151] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 07/01/2017] [Accepted: 01/30/2018] [Indexed: 12/30/2022] Open
Abstract
How endothelial cells sense and react to flow during vascular remodeling is poorly understood. Vion et al. show that endothelial cells utilize their primary cilia to stabilize vessel connections during vascular remodeling. Molecularly, they identify enhanced sensitivity to BMP9 in ciliated endothelial cells, selectively under low flow. Blood flow shapes vascular networks by orchestrating endothelial cell behavior and function. How endothelial cells read and interpret flow-derived signals is poorly understood. Here, we show that endothelial cells in the developing mouse retina form and use luminal primary cilia to stabilize vessel connections selectively in parts of the remodeling vascular plexus experiencing low and intermediate shear stress. Inducible genetic deletion of the essential cilia component intraflagellar transport protein 88 (IFT88) in endothelial cells caused premature and random vessel regression without affecting proliferation, cell cycle progression, or apoptosis. IFT88 mutant cells lacking primary cilia displayed reduced polarization against blood flow, selectively at low and intermediate flow levels, and have a stronger migratory behavior. Molecularly, we identify that primary cilia endow endothelial cells with strongly enhanced sensitivity to bone morphogenic protein 9 (BMP9), selectively under low flow. We propose that BMP9 signaling cooperates with the primary cilia at low flow to keep immature vessels open before high shear stress–mediated remodeling.
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Affiliation(s)
- Anne-Clémence Vion
- Max Delbrück Center for Molecular Medicine, Berlin, Germany .,Vascular Biology Laboratory, London Research Institute - Cancer Research UK, Lincoln's Inn Fields Laboratories, London, England, UK.,German Center for Cardiovascular Research, Berlin, Germany
| | - Silvanus Alt
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Alexandra Klaus-Bergmann
- Max Delbrück Center for Molecular Medicine, Berlin, Germany.,German Center for Cardiovascular Research, Berlin, Germany
| | - Anna Szymborska
- Max Delbrück Center for Molecular Medicine, Berlin, Germany.,German Center for Cardiovascular Research, Berlin, Germany
| | - Tuyu Zheng
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Tijana Perovic
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Adel Hammoutene
- Institut National de la Santé et de la Recherche Medicale, U970, Paris Cardiovascular Research Center, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | | | - Eireen Bartels-Klein
- Max Delbrück Center for Molecular Medicine, Berlin, Germany.,German Center for Cardiovascular Research, Berlin, Germany
| | | | - Pierre-Emmanuel Rautou
- Institut National de la Santé et de la Recherche Medicale, U970, Paris Cardiovascular Research Center, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Departement Hospitalo-Universitaire Unity, Pôle des Maladies de l'Appareil Digestif, Service d'Hépatologie, Centre de Référence des Maladies Vasculaires du Foie, Hôpital Beaujon, Assistance Publique - Hopitaux de Paris, Clichy, France
| | - Miguel O Bernabeu
- Centre for Medical Informatics, Usher Institute, University of Edinburgh, Edinburgh, Scotland, UK.,Centre for Computational Science, Department of Chemistry, University College London, London, England, UK
| | - Holger Gerhardt
- Max Delbrück Center for Molecular Medicine, Berlin, Germany .,Vascular Biology Laboratory, London Research Institute - Cancer Research UK, Lincoln's Inn Fields Laboratories, London, England, UK.,German Center for Cardiovascular Research, Berlin, Germany.,Vascular Patterning Laboratory, VIB Center for Cancer Biology, Leuven, Belgium.,Vascular Patterning Laboratory, Department of Oncology, KU Leuven, Leuven, Belgium.,Berlin Institute of Health, Berlin, Germany
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67
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He M, Ye W, Wang WJ, Sison ES, Jan YN, Jan LY. Cytoplasmic Cl - couples membrane remodeling to epithelial morphogenesis. Proc Natl Acad Sci U S A 2017; 114:E11161-E11169. [PMID: 29229864 PMCID: PMC5748203 DOI: 10.1073/pnas.1714448115] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Chloride is the major free anion in the extracellular space (>100 mM) and within the cytoplasm in eukaryotes (10 ∼ 20 mM). Cytoplasmic Cl- level is dynamically regulated by Cl- channels and transporters. It is well established that movement of Cl- across the cell membrane is coupled with cell excitability through changes in membrane potential and with water secretion. However, whether cytoplasmic Cl- plays additional roles in animal development and tissue homeostasis is unknown. Here we use genetics, cell biological and pharmacological tools to demonstrate that TMEM16A, an evolutionarily conserved calcium-activated chloride channel (CaCC), regulates cytoplasmic Cl- homeostasis and promotes plasma membrane remodeling required for mammalian epithelial morphogenesis. We demonstrate that TMEM16A-mediated control of cytoplasmic Cl- regulates the organization of the major phosphoinositide species PtdIns(4,5)P2 into microdomains on the plasma membrane, analogous to processes that cluster soluble and membrane proteins into phase-separated droplets. We further show that an adequate cytoplasmic Cl- level is required for proper endocytic trafficking and membrane supply during early stages of ciliogenesis and adherens junction remodeling. Our study thus uncovers a critical function of CaCC-mediated cytoplasmic Cl- homeostasis in controlling the organization of PtdIns(4,5)P2 microdomains and membrane remodeling. This newly defined role of cytoplasmic Cl- may shed light on the mechanisms of intracellular Cl- signaling events crucial for regulating tissue architecture and organelle biogenesis during animal development.
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Affiliation(s)
- Mu He
- Department of Physiology, University of California, San Francisco, CA 94158
| | - Wenlei Ye
- Department of Physiology, University of California, San Francisco, CA 94158
| | - Won-Jing Wang
- Institute of Biochemistry and Molecular Biology, College of Life Sciences, National Yang-Ming University, Taipei, 11221, Taiwan
| | - Eirish S Sison
- Department of Physiology, University of California, San Francisco, CA 94158
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94158
| | - Yuh Nung Jan
- Department of Physiology, University of California, San Francisco, CA 94158
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94158
| | - Lily Yeh Jan
- Department of Physiology, University of California, San Francisco, CA 94158;
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94158
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68
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Abstract
Cilia are microtubule-based organelles extending from a basal body at the surface of eukaryotic cells. Cilia regulate cell and fluid motility, sensation and developmental signaling, and ciliary defects cause human diseases (ciliopathies) affecting the formation and function of many tissues and organs. Over the past decade, various Rab and Rab-like membrane trafficking proteins have been shown to regulate cilia-related processes such as basal body maturation, ciliary axoneme extension, intraflagellar transport and ciliary signaling. In this review, we provide a comprehensive overview of Rab protein ciliary associations, drawing on findings from multiple model systems, including mammalian cell culture, mice, zebrafish, C. elegans, trypanosomes, and green algae. We also discuss several emerging mechanistic themes related to ciliary Rab cascades and functional redundancy.
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Affiliation(s)
- Oliver E Blacque
- a School of Biomolecular and Biomedical Science , University College Dublin , Belfield, Dublin , Ireland
| | - Noemie Scheidel
- a School of Biomolecular and Biomedical Science , University College Dublin , Belfield, Dublin , Ireland
| | - Stefanie Kuhns
- a School of Biomolecular and Biomedical Science , University College Dublin , Belfield, Dublin , Ireland
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69
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Mukhopadhyay S, Badgandi HB, Hwang SH, Somatilaka B, Shimada IS, Pal K. Trafficking to the primary cilium membrane. Mol Biol Cell 2017; 28:233-239. [PMID: 28082521 PMCID: PMC5231892 DOI: 10.1091/mbc.e16-07-0505] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 11/14/2016] [Accepted: 11/15/2016] [Indexed: 12/13/2022] Open
Abstract
The primary cilium has been found to be associated with a number of cellular signaling pathways, such as vertebrate hedgehog signaling, and implicated in the pathogenesis of diseases affecting multiple organs, including the neural tube, kidney, and brain. The primary cilium is the site where a subset of the cell's membrane proteins is enriched. However, pathways that target and concentrate membrane proteins in cilia are not well understood. Processes determining the level of proteins in the ciliary membrane include entry into the compartment, removal, and retention by diffusion barriers such as the transition zone. Proteins that are concentrated in the ciliary membrane are also localized to other cellular sites. Thus it is critical to determine the particular role for ciliary compartmentalization in sensory reception and signaling pathways. Here we provide a brief overview of our current understanding of compartmentalization of proteins in the ciliary membrane and the dynamics of trafficking into and out of the cilium. We also discuss major unanswered questions regarding the role that defects in ciliary compartmentalization might play in disease pathogenesis. Understanding the trafficking mechanisms that underlie the role of ciliary compartmentalization in signaling might provide unique approaches for intervention in progressive ciliopathies.
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Affiliation(s)
- Saikat Mukhopadhyay
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390
| | - Hemant B Badgandi
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390
| | - Sun-Hee Hwang
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390
| | | | - Issei S Shimada
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390
| | - Kasturi Pal
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390
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70
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Prevo B, Scholey JM, Peterman EJG. Intraflagellar transport: mechanisms of motor action, cooperation, and cargo delivery. FEBS J 2017; 284:2905-2931. [PMID: 28342295 PMCID: PMC5603355 DOI: 10.1111/febs.14068] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/20/2017] [Accepted: 03/23/2017] [Indexed: 02/06/2023]
Abstract
Intraflagellar transport (IFT) is a form of motor-dependent cargo transport that is essential for the assembly, maintenance, and length control of cilia, which play critical roles in motility, sensory reception, and signal transduction in virtually all eukaryotic cells. During IFT, anterograde kinesin-2 and retrograde IFT dynein motors drive the bidirectional transport of IFT trains that deliver cargo, for example, axoneme precursors such as tubulins as well as molecules of the signal transduction machinery, to their site of assembly within the cilium. Following its discovery in Chlamydomonas, IFT has emerged as a powerful model system for studying general principles of motor-dependent cargo transport and we now appreciate the diversity that exists in the mechanism of IFT within cilia of different cell types. The absence of heterotrimeric kinesin-2 function, for example, causes a complete loss of both IFT and cilia in Chlamydomonas, but following its loss in Caenorhabditis elegans, where its primary function is loading the IFT machinery into cilia, homodimeric kinesin-2-driven IFT persists and assembles a full-length cilium. Generally, heterotrimeric kinesin-2 and IFT dynein motors are thought to play widespread roles as core IFT motors, whereas homodimeric kinesin-2 motors are accessory motors that mediate different functions in a broad range of cilia, in some cases contributing to axoneme assembly or the delivery of signaling molecules but in many other cases their ciliary functions, if any, remain unknown. In this review, we focus on mechanisms of motor action, motor cooperation, and motor-dependent cargo delivery during IFT.
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Affiliation(s)
- Bram Prevo
- Department of Cellular & Molecular Medicine, University of California San Diego, CA, USA
- Ludwig Institute for Cancer Research, San Diego, CA, USA
| | - Jonathan M Scholey
- Department of Molecular & Cell Biology, University of California Davis, CA, USA
| | - Erwin J G Peterman
- Department of Physics and Astronomy and LaserLaB Amsterdam, Vrije Universiteit, Amsterdam, The Netherlands
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71
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Kohli P, Höhne M, Jüngst C, Bertsch S, Ebert LK, Schauss AC, Benzing T, Rinschen MM, Schermer B. The ciliary membrane-associated proteome reveals actin-binding proteins as key components of cilia. EMBO Rep 2017; 18:1521-1535. [PMID: 28710093 DOI: 10.15252/embr.201643846] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 06/06/2017] [Accepted: 06/13/2017] [Indexed: 01/01/2023] Open
Abstract
Primary cilia are sensory, antennae-like organelles present on the surface of many cell types. They have been involved in a variety of diseases collectively termed ciliopathies. As cilia are essential regulators of cell signaling, the composition of the ciliary membrane needs to be strictly regulated. To understand regulatory processes at the ciliary membrane, we report the targeting of a genetically engineered enzyme specifically to the ciliary membrane to allow biotinylation and identification of the membrane-associated proteome. Bioinformatic analysis of the comprehensive dataset reveals high-stoichiometric presence of actin-binding proteins inside the cilium. Immunofluorescence stainings and complementary interaction proteomic analyses confirm these findings. Depolymerization of branched F-actin causes further enrichment of the actin-binding and actin-related proteins in cilia, including Myosin 5a (Myo5a). Interestingly, Myo5a knockout decreases ciliation while enhanced levels of Myo5a are observed in cilia upon induction of ciliary disassembly. In summary, we present a novel approach to investigate dynamics of the ciliary membrane proteome in mammalian cells and identify actin-binding proteins as mechanosensitive components of cilia that might have important functions in cilia membrane dynamics.
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Affiliation(s)
- Priyanka Kohli
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Martin Höhne
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Christian Jüngst
- Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Sabine Bertsch
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Lena K Ebert
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Astrid C Schauss
- Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Markus M Rinschen
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany .,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
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72
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Christensen ST, Morthorst SK, Mogensen JB, Pedersen LB. Primary Cilia and Coordination of Receptor Tyrosine Kinase (RTK) and Transforming Growth Factor β (TGF-β) Signaling. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a028167. [PMID: 27638178 DOI: 10.1101/cshperspect.a028167] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Since the beginning of the millennium, research in primary cilia has revolutionized our way of understanding how cells integrate and organize diverse signaling pathways during vertebrate development and in tissue homeostasis. Primary cilia are unique sensory organelles that detect changes in their extracellular environment and integrate and transmit signaling information to the cell to regulate various cellular, developmental, and physiological processes. Many different signaling pathways have now been shown to rely on primary cilia to function properly, and mutations that lead to ciliary dysfunction are at the root of a pleiotropic group of diseases and syndromic disorders called ciliopathies. In this review, we present an overview of primary cilia-mediated regulation of receptor tyrosine kinase (RTK) and transforming growth factor β (TGF-β) signaling. Further, we discuss how defects in the coordination of these pathways may be linked to ciliopathies.
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Affiliation(s)
- Søren T Christensen
- Department of Biology, University of Copenhagen, DK-2100 Copenhagen OE, Denmark
| | - Stine K Morthorst
- Department of Biology, University of Copenhagen, DK-2100 Copenhagen OE, Denmark
| | - Johanne B Mogensen
- Department of Biology, University of Copenhagen, DK-2100 Copenhagen OE, Denmark
| | - Lotte B Pedersen
- Department of Biology, University of Copenhagen, DK-2100 Copenhagen OE, Denmark
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73
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Wilcockson SG, Sutcliffe C, Ashe HL. Control of signaling molecule range during developmental patterning. Cell Mol Life Sci 2017; 74:1937-1956. [PMID: 27999899 PMCID: PMC5418326 DOI: 10.1007/s00018-016-2433-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/24/2016] [Accepted: 12/05/2016] [Indexed: 12/22/2022]
Abstract
Tissue patterning, through the concerted activity of a small number of signaling pathways, is critical to embryonic development. While patterning can involve signaling between neighbouring cells, in other contexts signals act over greater distances by traversing complex cellular landscapes to instruct the fate of distant cells. In this review, we explore different strategies adopted by cells to modulate signaling molecule range to allow correct patterning. We describe mechanisms for restricting signaling range and highlight how such short-range signaling can be exploited to not only control the fate of adjacent cells, but also to generate graded signaling within a field of cells. Other strategies include modulation of signaling molecule action by tissue architectural properties and the use of cellular membranous structures, such as signaling filopodia and exosomes, to actively deliver signaling ligands to target cells. Signaling filopodia can also be deployed to reach out and collect particular signals, thereby precisely controlling their site of action.
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Affiliation(s)
- Scott G Wilcockson
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Catherine Sutcliffe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Hilary L Ashe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK.
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74
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Shimada IS, Badgandi H, Somatilaka BN, Mukhopadhyay S. Using Primary Neurosphere Cultures to Study Primary Cilia. J Vis Exp 2017. [PMID: 28448009 DOI: 10.3791/55315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The primary cilium is fundamentally important for the proliferation of neural stem/progenitor cells and for neuronal differentiation during embryonic, postnatal, and adult life. In addition, most differentiated neurons possess primary cilia that house signaling receptors, such as G-protein-coupled receptors, and signaling molecules, such as adenylyl cyclases. The primary cilium determines the activity of multiple developmental pathways, including the sonic hedgehog pathway during embryonic neuronal development, and also functions in promoting compartmentalized subcellular signaling during adult neuronal function. Unsurprisingly, defects in primary cilium biogenesis and function have been linked to developmental anomalies of the brain, central obesity, and learning and memory deficits. Thus, it is imperative to study primary cilium biogenesis and ciliary trafficking in the context of neural stem/progenitor cells and differentiated neurons. However, culturing methods for primary neurons require considerable expertise and are not amenable to freeze-thaw cycles. In this protocol, we discuss culturing methods for mixed populations of neural stem/progenitor cells using primary neurospheres. The neurosphere-based culturing methods provide the combined benefits of studying primary neural stem/progenitor cells: amenability to multiple passages and freeze-thaw cycles, differentiation potential into neurons/glia, and transfectability. Importantly, we determined that neurosphere-derived neural stem/progenitor cells and differentiated neurons are ciliated in culture and localize signaling molecules relevant to ciliary function in these compartments. Utilizing these cultures, we further describe methods to study ciliogenesis and ciliary trafficking in neural stem/progenitor cells and differentiated neurons. These neurosphere-based methods allow us to study cilia-regulated cellular pathways, including G-protein-coupled receptor and sonic hedgehog signaling, in the context of neural stem/progenitor cells and differentiated neurons.
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Affiliation(s)
- Issei S Shimada
- Department of Cell Biology, University of Texas Southwestern Medical Center;
| | - Hemant Badgandi
- Department of Cell Biology, University of Texas Southwestern Medical Center
| | | | - Saikat Mukhopadhyay
- Department of Cell Biology, University of Texas Southwestern Medical Center;
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75
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Urrego D, Sánchez A, Tomczak AP, Pardo LA. The electric fence to cell-cycle progression: Do local changes in membrane potential facilitate disassembly of the primary cilium? Bioessays 2017; 39. [DOI: 10.1002/bies.201600190] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Diana Urrego
- Max-Planck-Institut für experimentelle Medizin; AG Oncophysiology; Göttingen Germany
| | - Araceli Sánchez
- Max-Planck-Institut für experimentelle Medizin; AG Oncophysiology; Göttingen Germany
| | - Adam P. Tomczak
- Max-Planck-Institut für experimentelle Medizin; AG Oncophysiology; Göttingen Germany
| | - Luis A. Pardo
- Max-Planck-Institut für experimentelle Medizin; AG Oncophysiology; Göttingen Germany
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76
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Badgandi HB, Hwang SH, Shimada IS, Loriot E, Mukhopadhyay S. Tubby family proteins are adapters for ciliary trafficking of integral membrane proteins. J Cell Biol 2017; 216:743-760. [PMID: 28154160 PMCID: PMC5350516 DOI: 10.1083/jcb.201607095] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/25/2016] [Accepted: 01/09/2017] [Indexed: 01/19/2023] Open
Abstract
Trafficking of integral membrane proteins to cilia is poorly understood. Badgandi et al. show that tubby family proteins TULP3 and TUB act as general adapters for ciliary trafficking of structurally diverse integral membrane cargo like GCPRs and the polycystin 1/2 complex. The primary cilium is a paradigmatic organelle for studying compartmentalized signaling; however, unlike soluble protein trafficking, processes targeting integral membrane proteins to cilia are poorly understood. In this study, we determine that the tubby family protein TULP3 functions as a general adapter for ciliary trafficking of structurally diverse integral membrane cargo, including multiple reported and novel rhodopsin family G protein–coupled receptors (GPCRs) and the polycystic kidney disease–causing polycystin 1/2 complex. The founding tubby family member TUB also localizes to cilia similar to TULP3 and determines trafficking of a subset of these GPCRs to neuronal cilia. Using minimal ciliary localization sequences from GPCRs and fibrocystin (also implicated in polycystic kidney disease), we demonstrate these motifs to be sufficient and TULP3 dependent for ciliary trafficking. We propose a three-step model for TULP3/TUB-mediated ciliary trafficking, including the capture of diverse membrane cargo by the tubby domain in a phosphoinositide 4,5-bisphosphate (PI(4,5)P2)-dependent manner, ciliary delivery by intraflagellar transport complex A binding to the TULP3/TUB N terminus, and subsequent release into PI(4,5)P2-deficient ciliary membrane.
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Affiliation(s)
- Hemant B Badgandi
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Sun-Hee Hwang
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Issei S Shimada
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Evan Loriot
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390.,STARS Program, University of Texas Southwestern Medical Center, Dallas, TX 75390.,Jesuit College Preparatory School of Dallas, Dallas, TX 75244
| | - Saikat Mukhopadhyay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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77
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Hirano T, Katoh Y, Nakayama K. Intraflagellar transport-A complex mediates ciliary entry and retrograde trafficking of ciliary G protein-coupled receptors. Mol Biol Cell 2017; 28:429-439. [PMID: 27932497 PMCID: PMC5341726 DOI: 10.1091/mbc.e16-11-0813] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 12/01/2016] [Indexed: 12/19/2022] Open
Abstract
Cilia serve as cellular antennae where proteins involved in sensory and developmental signaling, including G protein-coupled receptors (GPCRs), are specifically localized. Intraflagellar transport (IFT)-A and -B complexes mediate retrograde and anterograde ciliary protein trafficking, respectively. Using a visible immunoprecipitation assay to detect protein-protein interactions, we show that the IFT-A complex is divided into a core subcomplex, composed of IFT122/IFT140/IFT144, which is associated with TULP3, and a peripheral subcomplex, composed of IFT43/IFT121/IFT139, where IFT139 is most distally located. IFT139-knockout (KO) and IFT144-KO cells demonstrated distinct phenotypes: IFT139-KO cells showed the accumulation of IFT-A, IFT-B, and GPCRs, including Smoothened and GPR161, at the bulged ciliary tips; IFT144-KO cells showed failed ciliary entry of IFT-A and GPCRs and IFT-B accumulation at the bulged tips. These observations demonstrate the distinct roles of the core and peripheral IFT-A subunits: IFT139 is dispensable for IFT-A assembly but essential for retrograde trafficking of IFT-A, IFT-B, and GPCRs; in contrast, IFT144 is essential for functional IFT-A assembly and ciliary entry of GPCRs but dispensable for anterograde IFT-B trafficking. Thus the data presented here demonstrate that the IFT-A complex mediates not only retrograde trafficking but also entry into cilia of GPCRs.
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Affiliation(s)
- Tomoaki Hirano
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yohei Katoh
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kazuhisa Nakayama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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78
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Pablo JL, DeCaen PG, Clapham DE. Progress in ciliary ion channel physiology. J Gen Physiol 2016; 149:37-47. [PMID: 27999145 PMCID: PMC5217089 DOI: 10.1085/jgp.201611696] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 12/06/2016] [Indexed: 11/20/2022] Open
Abstract
Mammalian cilia are ubiquitous appendages found on the apical surface of cells. Primary and motile cilia are distinct in both morphology and function. Most cells have a solitary primary cilium (9+0), which lacks the central microtubule doublet characteristic of motile cilia (9+2). The immotile primary cilia house unique signaling components and sequester several important transcription factors. In contrast, motile cilia commonly extend into the lumen of respiratory airways, fallopian tubes, and brain ventricles to move their contents and/or produce gradients. In this review, we focus on the composition of putative ion channels found in both types of cilia and in the periciliary membrane and discuss their proposed functions. Our discussion does not cover specialized cilia in photoreceptor or olfactory cells, which express many more ion channels.
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Affiliation(s)
- Juan Lorenzo Pablo
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115.,Department of Cardiology, Boston Children's Hospital, Boston, MA 02115.,Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Paul G DeCaen
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - David E Clapham
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115 .,Department of Cardiology, Boston Children's Hospital, Boston, MA 02115.,Department of Neurobiology, Harvard Medical School, Boston, MA 02115
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79
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Lepanto P, Badano JL, Zolessi FR. Neuron's little helper: The role of primary cilia in neurogenesis. NEUROGENESIS 2016; 3:e1253363. [PMID: 28090545 DOI: 10.1080/23262133.2016.1253363] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/09/2016] [Accepted: 10/20/2016] [Indexed: 01/27/2023]
Abstract
The generation of new neurons involves a great variety of cell-extrinsic and cell-intrinsic signals. The primary cilium, long regarded as an "evolutionary vestige," has emerged as an essential signaling hub in many cells, including neural progenitors and differentiating neurons. Most progenitors harbor an apically-localized primary cilium, which is assembled and disassembled following the cell cycle, while the presence, position and length of this organelle appears to be even more variable in differentiating neurons. One of the main extracellular cues acting through the cilium is Sonic Hedgehog, which modulates spatial patterning, the progression of the cell cycle and the timing of neurogenesis. Other extracellular signals appear to bind to cilia-localized receptors and affect processes such as dendritogenesis. All the observed dynamics, as well as the many signaling pathways depending on cilia, indicate this organelle as an important structure involved in neurogenesis.
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Affiliation(s)
- Paola Lepanto
- Cell Biology of Neural Development Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay; Human Molecular Genetics Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Jose L Badano
- Human Molecular Genetics Laboratory, Institut Pasteur de Montevideo , Montevideo, Uruguay
| | - Flavio R Zolessi
- Cell Biology of Neural Development Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay; Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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80
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Mourão A, Christensen ST, Lorentzen E. The intraflagellar transport machinery in ciliary signaling. Curr Opin Struct Biol 2016; 41:98-108. [PMID: 27393972 DOI: 10.1016/j.sbi.2016.06.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 06/07/2016] [Indexed: 01/12/2023]
Abstract
Cilia and flagella on eukaryotic cells are slender microtubule-based projections surrounded by a membrane with a unique lipid and protein composition. It is now appreciated that cilia in addition to their established roles in motility also constitute hubs for cellular signaling by sensing external environmental cues necessary for organ development and maintenance of human health. Pathways reported to rely on the cilium organelle include Hedgehog, TGF-β, Wnt, PDGFRα, integrin and DNA damage repair signaling. An emerging theme in ciliary signaling is the requirement for active transport of signaling components into and out of the cilium proper. Here, we review the current state-of-the-art regarding the importance of intraflagellar transport and BBSome multi-subunit complexes in ciliary signaling.
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Affiliation(s)
- André Mourão
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Søren T Christensen
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen, Denmark.
| | - Esben Lorentzen
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany.
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