1
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Refai O, Rodriguez P, Gichi Z, Blakely RD. Forward genetic screen of the C. elegans million mutation library reveals essential, cell-autonomous contributions of BBSome proteins to dopamine signaling. J Neurochem 2024. [PMID: 39118406 DOI: 10.1111/jnc.16188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 07/11/2024] [Accepted: 07/12/2024] [Indexed: 08/10/2024]
Abstract
The nematode Caenorhabditis elegans is well known for its ability to support forward genetic screens to identify molecules involved in neuronal viability and signaling. The proteins involved in C. elegans dopamine (DA) regulation are highly conserved across evolution, with prior work demonstrating that the model can serve as an efficient platform to identify novel genes involved in disease-associated processes. To identify novel players in DA signaling, we took advantage of a recently developed library of pre-sequenced mutant nematodes arising from the million mutation project (MMP) to identify strains that display the DA-dependent swimming-induced-paralysis phenotype (Swip). Our screen identified novel mutations in the dopamine transporter encoding gene dat-1, whose loss was previously used to identify the Swip phenotype, as well as multiple genes with previously unknown connections to DA signaling. Here, we present our isolation and characterization of one of these genes, bbs-1, previously linked to the function of primary cilia in worms and higher organisms, including humans, and where loss-of-function mutations result in a human disorder known as Bardet-Biedl syndrome. Our studies of C. elegans BBS-1 protein, as well as other proteins that are known to be assembled into a higher order complex (the BBSome) reveal that functional or structural disruption of this complex leads to exaggerated C. elegans DA signaling to produce Swip via a cell-autonomous mechanism. We provide evidence that not only does the proper function of cilia in C. elegans DA neurons support normal swimming behavior, but also that bbs-1 maintains normal levels of DAT-1 trafficking or function via a RHO-1 and SWIP-13/MAPK-15 dependent pathway where mutants may contribute to Swip independent of altered ciliary function. Together, these studies demonstrate novel contributors to DA neuron function in the worm and demonstrate the utility and efficiency of forward genetic screens using the MMP library.
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Affiliation(s)
- Osama Refai
- Department of Biomedical Science, Florida Atlantic University, Boca Raton, Florida, USA
| | - Peter Rodriguez
- Department of Biomedical Science, Florida Atlantic University, Boca Raton, Florida, USA
| | - Zayna Gichi
- Department of Biomedical Science, Florida Atlantic University, Boca Raton, Florida, USA
| | - Randy D Blakely
- Department of Biomedical Science, Florida Atlantic University, Boca Raton, Florida, USA
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, Florida, USA
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2
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Pincay J, Rodriguez M, Kaushal D, Tsang SH. Rod-sparing in a bardet-biedl syndrome patient with mutations in the ARL6 gene. Doc Ophthalmol 2024:10.1007/s10633-024-09985-8. [PMID: 39078565 DOI: 10.1007/s10633-024-09985-8] [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: 06/04/2024] [Accepted: 07/16/2024] [Indexed: 07/31/2024]
Abstract
PURPOSE Bardet-Biedl Syndrome (BBS) is an autosomal recessive disorder characterized by pleiotropism that affects multiple organ systems. The primary features of BBS include rod-cone dystrophy, renal anomalies, post axial polydactyly, and neurologic deficits. The clinical picture of BBS is extensively heterogenous, with inter and intra familial patients varying in levels of syndromic manifestations and severity of symptoms. METHODS In this study we examined a monocular BBS patient who was compound heterozygous for mutations in the ARL6 (BBS3) gene. RESULTS The patient reported visual complaints consistent with a clinical picture of cone or cone-rod dystrophy. Fundus imaging showed retinal mottling on color photos and a parafoveal hyperfluorescent ring on short wave autofluorescence (SW-AF). Full field electroretinogram (ffERG) revealed normal scotopic step tracings and diminished amplitudes in the photopic steps. CONCLUSION This rod-sparing result was consistent with cone-dystrophy and is the first known case of a rod-sparing ffERG phenotype in a BBS patient with mutations in the ARL6 gene. This contributes to the existing phenotype and may potentially contribute to furthering our understanding of BBS pathophysiology.
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Affiliation(s)
- Jorge Pincay
- Department of Ophthalmology, Columbia University Irving Medical Center, Vanderbilt Clinic 622 W 168th St 3rd Floor, New York, NY, 10032, USA
- State University of New York at Downstate Medical Center, Brooklyn, NY, USA
| | - Marilyn Rodriguez
- Department of Ophthalmology, Columbia University Irving Medical Center, Vanderbilt Clinic 622 W 168th St 3rd Floor, New York, NY, 10032, USA
| | - Divya Kaushal
- Department of Ophthalmology, Columbia University Irving Medical Center, Vanderbilt Clinic 622 W 168th St 3rd Floor, New York, NY, 10032, USA
| | - Stephen H Tsang
- Department of Ophthalmology, Columbia University Irving Medical Center, Vanderbilt Clinic 622 W 168th St 3rd Floor, New York, NY, 10032, USA.
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.
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3
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Yuan X, Kadowaki T. Protein subcellular relocalization and function of duplicated flagellar calcium binding protein genes in honey bee trypanosomatid parasite. PLoS Genet 2024; 20:e1011195. [PMID: 38437202 PMCID: PMC10939215 DOI: 10.1371/journal.pgen.1011195] [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: 06/22/2023] [Revised: 03/14/2024] [Accepted: 02/23/2024] [Indexed: 03/06/2024] Open
Abstract
The honey bee trypanosomatid parasite, Lotmaria passim, contains two genes that encode the flagellar calcium binding protein (FCaBP) through tandem duplication in its genome. FCaBPs localize in the flagellum and entire body membrane of L. passim through specific N-terminal sorting sequences. This finding suggests that this is an example of protein subcellular relocalization resulting from gene duplication, altering the intracellular localization of FCaBP. However, this phenomenon may not have occurred in Leishmania, as one or both of the duplicated genes have become pseudogenes. Multiple copies of the FCaBP gene are present in several Trypanosoma species and Leptomonas pyrrhocoris, indicating rapid evolution of this gene in trypanosomatid parasites. The N-terminal flagellar sorting sequence of L. passim FCaBP1 is in close proximity to the BBSome complex, while that of Trypanosoma brucei FCaBP does not direct GFP to the flagellum in L. passim. Deletion of the two FCaBP genes in L. passim affected growth and impaired flagellar morphogenesis and motility, but it did not impact host infection. Therefore, FCaBP represents a duplicated gene with a rapid evolutionary history that is essential for flagellar structure and function in a trypanosomatid parasite.
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Affiliation(s)
- Xuye Yuan
- Department of Biological Sciences, School of Science, Xi'an Jiaotong-Liverpool University, Suzhou Dushu Lake Higher Education Town, Jiangsu Province, China
| | - Tatsuhiko Kadowaki
- Department of Biological Sciences, School of Science, Xi'an Jiaotong-Liverpool University, Suzhou Dushu Lake Higher Education Town, Jiangsu Province, China
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4
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Niedziółka SM, Datta S, Uśpieński T, Baran B, Skarżyńska W, Humke EW, Rohatgi R, Niewiadomski P. The exocyst complex and intracellular vesicles mediate soluble protein trafficking to the primary cilium. Commun Biol 2024; 7:213. [PMID: 38378792 PMCID: PMC10879184 DOI: 10.1038/s42003-024-05817-2] [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: 03/17/2022] [Accepted: 01/15/2024] [Indexed: 02/22/2024] Open
Abstract
The efficient transport of proteins into the primary cilium is a crucial step for many signaling pathways. Dysfunction of this process can lead to the disruption of signaling cascades or cilium assembly, resulting in developmental disorders and cancer. Previous studies on the protein delivery to the cilium were mostly focused on the membrane-embedded receptors. In contrast, how soluble proteins are delivered into the cilium is poorly understood. In our work, we identify the exocyst complex as a key player in the ciliary trafficking of soluble Gli transcription factors. In line with the known function of the exocyst in intracellular vesicle transport, we demonstrate that soluble proteins, including Gli2/3 and Lkb1, can use the endosome recycling machinery for their delivery to the primary cilium. Finally, we identify GTPases: Rab14, Rab18, Rab23, and Arf4 that are involved in vesicle-mediated Gli protein ciliary trafficking. Our data pave the way for a better understanding of ciliary transport and uncover transport mechanisms inside the cell.
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Affiliation(s)
- S M Niedziółka
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - S Datta
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - T Uśpieński
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - B Baran
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - W Skarżyńska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - E W Humke
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- IGM Biosciences, Inc, Mountain View, CA, USA
| | - R Rohatgi
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - P Niewiadomski
- Centre of New Technologies, University of Warsaw, Warsaw, Poland.
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5
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Rao L, Gennerich A. Structure and Function of Dynein's Non-Catalytic Subunits. Cells 2024; 13:330. [PMID: 38391943 PMCID: PMC10886578 DOI: 10.3390/cells13040330] [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: 01/15/2024] [Revised: 02/05/2024] [Accepted: 02/09/2024] [Indexed: 02/24/2024] Open
Abstract
Dynein, an ancient microtubule-based motor protein, performs diverse cellular functions in nearly all eukaryotic cells, with the exception of land plants. It has evolved into three subfamilies-cytoplasmic dynein-1, cytoplasmic dynein-2, and axonemal dyneins-each differentiated by their cellular functions. These megadalton complexes consist of multiple subunits, with the heavy chain being the largest subunit that generates motion and force along microtubules by converting the chemical energy of ATP hydrolysis into mechanical work. Beyond this catalytic core, the functionality of dynein is significantly enhanced by numerous non-catalytic subunits. These subunits are integral to the complex, contributing to its stability, regulating its enzymatic activities, targeting it to specific cellular locations, and mediating its interactions with other cofactors. The diversity of non-catalytic subunits expands dynein's cellular roles, enabling it to perform critical tasks despite the conservation of its heavy chains. In this review, we discuss recent findings and insights regarding these non-catalytic subunits.
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Affiliation(s)
- Lu Rao
- Department of Biochemistry and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Arne Gennerich
- Department of Biochemistry and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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6
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Udupa P, Ghosh DK. The emerging functions of intraflagellar transport 52 in ciliary transport and ciliopathies. Traffic 2024; 25:e12929. [PMID: 38272449 DOI: 10.1111/tra.12929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/31/2023] [Accepted: 12/26/2023] [Indexed: 01/27/2024]
Abstract
Ciliary transport in eukaryotic cells is an intricate and conserved process involving the coordinated assembly and functioning of a multiprotein intraflagellar transport (IFT) complex. Among the various IFT proteins, intraflagellar transport 52 (IFT52) plays a crucial role in ciliary transport and is implicated in various ciliopathies. IFT52 is a core component of the IFT-B complex that facilitates movement of cargoes along the ciliary axoneme. Stable binding of the IFT-B1 and IFT-B2 subcomplexes by IFT52 in the IFT-B complex regulates recycling of ciliary components and maintenance of ciliary functions such as signal transduction and molecular movement. Mutations in the IFT52 gene can disrupt ciliary trafficking, resulting in dysfunctional cilia and affecting cellular processes in ciliopathies. Such ciliopathies caused by IFT52 mutations exhibit a wide range of clinical features, including skeletal developmental abnormalities, retinal degeneration, respiratory failure and neurological abnormalities in affected individuals. Therefore, IFT52 serves as a promising biomarker for the diagnosis of various ciliopathies, including short-rib thoracic dysplasia 16 with or without polydactyly. Here, we provide an overview of the IFT52-mediated molecular mechanisms underlying ciliary transport and describe the IFT52 mutations that cause different disorders associated with cilia dysfunction.
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Affiliation(s)
- Prajna Udupa
- Kasturba Medical College, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Debasish Kumar Ghosh
- Kasturba Medical College, Manipal Academy of Higher Education, Manipal, Karnataka, India
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7
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Tasaki K, Zhou Z, Ishida Y, Katoh Y, Nakayama K. Compound heterozygous IFT81 variations in a skeletal ciliopathy patient cause Bardet-Biedl syndrome-like ciliary defects. Hum Mol Genet 2023; 32:2887-2900. [PMID: 37427975 DOI: 10.1093/hmg/ddad112] [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: 04/28/2023] [Revised: 07/04/2023] [Accepted: 07/04/2023] [Indexed: 07/11/2023] Open
Abstract
Owing to their crucial roles in development and homeostasis, defects in cilia cause ciliopathies with diverse clinical manifestations. The intraflagellar transport (IFT) machinery, containing the IFT-A and IFT-B complexes, mediates not only the intraciliary bidirectional trafficking but also import and export of ciliary proteins together with the kinesin-2 and dynein-2 motor complexes. The BBSome, containing eight subunits encoded by causative genes of Bardet-Biedl syndrome (BBS), connects the IFT machinery to ciliary membrane proteins to mediate their export from cilia. Although mutations in subunits of the IFT-A and dynein-2 complexes cause skeletal ciliopathies, mutations in some IFT-B subunits are also known to cause skeletal ciliopathies. We here show that compound heterozygous variations of an IFT-B subunit, IFT81, found in a patient with skeletal ciliopathy cause defects in its interactions with other IFT-B subunits, and in ciliogenesis and ciliary protein trafficking when one of the two variants was expressed in IFT81-knockout (KO) cells. Notably, we found that IFT81-KO cells expressing IFT81(Δ490-519), which lacks the binding site for the IFT25-IFT27 dimer, causes ciliary defects reminiscent of those found in BBS cells and those in IFT74-KO cells expressing a BBS variant of IFT74, which forms a heterodimer with IFT81. In addition, IFT81-KO cells expressing IFT81(Δ490-519) in combination with the other variant, IFT81 (L645*), which mimics the cellular conditions of the above skeletal ciliopathy patient, demonstrated essentially the same phenotype as those expressing only IFT81(Δ490-519). Thus, our data indicate that BBS-like defects can be caused by skeletal ciliopathy variants of IFT81.
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Affiliation(s)
- Koshi Tasaki
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Zhuang Zhou
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Yamato Ishida
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Yohei Katoh
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Kazuhisa Nakayama
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
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8
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Clearman KR, Haycraft CJ, Croyle MJ, Collawn JF, Yoder BK. Functions of the primary cilium in the kidney and its connection with renal diseases. Curr Top Dev Biol 2023; 155:39-94. [PMID: 38043952 DOI: 10.1016/bs.ctdb.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The nonmotile primary cilium is a sensory structure found on most mammalian cell types that integrates multiple signaling pathways involved in tissue development and postnatal function. As such, mutations disrupting cilia activities cause a group of disorders referred to as ciliopathies. These disorders exhibit a wide spectrum of phenotypes impacting nearly every tissue. In the kidney, primary cilia dysfunction caused by mutations in polycystin 1 (Pkd1), polycystin 2 (Pkd2), or polycystic kidney and hepatic disease 1 (Pkhd1), result in polycystic kidney disease (PKD), a progressive disorder causing renal functional decline and end-stage renal disease. PKD affects nearly 1 in 1000 individuals and as there is no cure for PKD, patients frequently require dialysis or renal transplantation. Pkd1, Pkd2, and Pkhd1 encode membrane proteins that all localize in the cilium. Pkd1 and Pkd2 function as a nonselective cation channel complex while Pkhd1 protein function remains uncertain. Data indicate that the cilium may act as a mechanosensor to detect fluid movement through renal tubules. Other functions proposed for the cilium and PKD proteins in cyst development involve regulation of cell cycle and oriented division, regulation of renal inflammation and repair processes, maintenance of epithelial cell differentiation, and regulation of mitochondrial structure and metabolism. However, how loss of cilia or cilia function leads to cyst development remains elusive. Studies directed at understanding the roles of Pkd1, Pkd2, and Pkhd1 in the cilium and other locations within the cell will be important for developing therapeutic strategies to slow cyst progression.
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Affiliation(s)
- Kelsey R Clearman
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Courtney J Haycraft
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mandy J Croyle
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States.
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9
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Weng Z, Zheng J, Zhou Y, Lu Z, Wu Y, Xu D, Li H, Liang H, Liu Y. Structural and mechanistic insights into the MCM8/9 helicase complex. eLife 2023; 12:RP87468. [PMID: 37535404 PMCID: PMC10400076 DOI: 10.7554/elife.87468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2023] Open
Abstract
MCM8 and MCM9 form a functional helicase complex (MCM8/9) that plays an essential role in DNA homologous recombination repair for DNA double-strand break. However, the structural characterization of MCM8/9 for DNA binding/unwinding remains unclear. Here, we report structures of the MCM8/9 complex using cryo-electron microscopy single particle analysis. The structures reveal that MCM8/9 is arranged into a heterohexamer through a threefold symmetry axis, creating a central channel that accommodates DNA. Multiple characteristic hairpins from the N-terminal oligosaccharide/oligonucleotide (OB) domains of MCM8/9 protrude into the central channel and serve to unwind the duplex DNA. When activated by HROB, the structure of MCM8/9's N-tier ring converts its symmetry from C3 to C1 with a conformational change that expands the MCM8/9's trimer interface. Moreover, our structural dynamic analyses revealed that the flexible C-tier ring exhibited rotary motions relative to the N-tier ring, which is required for the unwinding ability of MCM8/9. In summary, our structural and biochemistry study provides a basis for understanding the DNA unwinding mechanism of MCM8/9 helicase in homologous recombination.
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Affiliation(s)
- Zhuangfeng Weng
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Jiefu Zheng
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Yiyi Zhou
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Zuer Lu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Yixi Wu
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Dongyi Xu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Huanhuan Li
- Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Guangzhou, China
| | - Huanhuan Liang
- Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen, China
| | - Yingfang Liu
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Guangzhou, China
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10
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Tian X, Zhao H, Zhou J. Organization, functions, and mechanisms of the BBSome in development, ciliopathies, and beyond. eLife 2023; 12:e87623. [PMID: 37466224 DOI: 10.7554/elife.87623] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/06/2023] [Indexed: 07/20/2023] Open
Abstract
The BBSome is an octameric protein complex that regulates ciliary transport and signaling. Mutations in BBSome subunits are closely associated with ciliary defects and lead to ciliopathies, notably Bardet-Biedl syndrome. Over the past few years, there has been significant progress in elucidating the molecular organization and functions of the BBSome complex. An improved understanding of BBSome-mediated biological events and molecular mechanisms is expected to help advance the development of diagnostic and therapeutic approaches for BBSome-related diseases. Here, we review the current literature on the structural assembly, transport regulation, and molecular functions of the BBSome, emphasizing its roles in cilium-related processes. We also provide perspectives on the pathological role of the BBSome in ciliopathies as well as how these can be exploited for therapeutic benefit.
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Affiliation(s)
- Xiaoyu Tian
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Huijie Zhao
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jun Zhou
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, College of Life Sciences, Nankai University, Tianjin, China
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11
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Mill P, Christensen ST, Pedersen LB. Primary cilia as dynamic and diverse signalling hubs in development and disease. Nat Rev Genet 2023; 24:421-441. [PMID: 37072495 PMCID: PMC7615029 DOI: 10.1038/s41576-023-00587-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 67.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2023] [Indexed: 04/20/2023]
Abstract
Primary cilia, antenna-like sensory organelles protruding from the surface of most vertebrate cell types, are essential for regulating signalling pathways during development and adult homeostasis. Mutations in genes affecting cilia cause an overlapping spectrum of >30 human diseases and syndromes, the ciliopathies. Given the immense structural and functional diversity of the mammalian cilia repertoire, there is a growing disconnect between patient genotype and associated phenotypes, with variable severity and expressivity characteristic of the ciliopathies as a group. Recent technological developments are rapidly advancing our understanding of the complex mechanisms that control biogenesis and function of primary cilia across a range of cell types and are starting to tackle this diversity. Here, we examine the structural and functional diversity of primary cilia, their dynamic regulation in different cellular and developmental contexts and their disruption in disease.
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Affiliation(s)
- Pleasantine Mill
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
| | | | - Lotte B Pedersen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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12
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Ning K, Bhuckory MB, Lo CH, Sendayen BE, Kowal TJ, Chen M, Bansal R, Chang KC, Vollrath D, Berbari NF, Mahajan VB, Hu Y, Sun Y. Cilia-associated wound repair mediated by IFT88 in retinal pigment epithelium. Sci Rep 2023; 13:8205. [PMID: 37211572 PMCID: PMC10200793 DOI: 10.1038/s41598-023-35099-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 05/12/2023] [Indexed: 05/23/2023] Open
Abstract
Primary cilia are conserved organelles that integrate extracellular cues into intracellular signals and are critical for diverse processes, including cellular development and repair responses. Deficits in ciliary function cause multisystemic human diseases known as ciliopathies. In the eye, atrophy of the retinal pigment epithelium (RPE) is a common feature of many ciliopathies. However, the roles of RPE cilia in vivo remain poorly understood. In this study, we first found that mouse RPE cells only transiently form primary cilia. We then examined the RPE in the mouse model of Bardet-Biedl Syndrome 4 (BBS4), a ciliopathy associated with retinal degeneration in humans, and found that ciliation in BBS4 mutant RPE cells is disrupted early during development. Next, using a laser-induced injury model in vivo, we found that primary cilia in RPE reassemble in response to laser injury during RPE wound healing and then rapidly disassemble after the repair is completed. Finally, we demonstrated that RPE-specific depletion of primary cilia in a conditional mouse model of cilia loss promoted wound healing and enhanced cell proliferation. In summary, our data suggest that RPE cilia contribute to both retinal development and repair and provide insights into potential therapeutic targets for more common RPE degenerative diseases.
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Affiliation(s)
- Ke Ning
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Mohajeet B Bhuckory
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Chien-Hui Lo
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Brent E Sendayen
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
- Palo Alto Veterans Administration, Palo Alto, CA, USA
| | - Tia J Kowal
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Ming Chen
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Ruchi Bansal
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Kun-Che Chang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Douglas Vollrath
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
- Department of Genetics, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Nicolas F Berbari
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Vinit B Mahajan
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA, 94304, USA.
- Palo Alto Veterans Administration, Palo Alto, CA, USA.
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13
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Karam A, Delvallée C, Estrada-Cuzcano A, Geoffroy V, Lamouche JB, Leuvrey AS, Nourisson E, Tarabeux J, Stoetzel C, Scheidecker S, Porter LF, Génin E, Redon R, Sandron F, Boland A, Deleuze JF, Le May N, Dollfus H, Muller J. WGS Revealed Novel BBS5 Pathogenic Variants, Missed by WES, Causing Ciliary Structure and Function Defects. Int J Mol Sci 2023; 24:8729. [PMID: 37240074 PMCID: PMC10218572 DOI: 10.3390/ijms24108729] [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: 03/31/2023] [Revised: 04/18/2023] [Accepted: 04/24/2023] [Indexed: 05/28/2023] Open
Abstract
Bardet-Biedl syndrome (BBS) is an autosomal recessive ciliopathy that affects multiple organs, leading to retinitis pigmentosa, polydactyly, obesity, renal anomalies, cognitive impairment, and hypogonadism. Until now, biallelic pathogenic variants have been identified in at least 24 genes delineating the genetic heterogeneity of BBS. Among those, BBS5 is a minor contributor to the mutation load and is one of the eight subunits forming the BBSome, a protein complex implied in protein trafficking within the cilia. This study reports on a European BBS5 patient with a severe BBS phenotype. Genetic analysis was performed using multiple next-generation sequencing (NGS) tests (targeted exome, TES and whole exome, WES), and biallelic pathogenic variants could only be identified using whole-genome sequencing (WGS), including a previously missed large deletion of the first exons. Despite the absence of family samples, the biallelic status of the variants was confirmed. The BBS5 protein's impact was confirmed on the patient's cells (presence/absence and size of the cilium) and ciliary function (Sonic Hedgehog pathway). This study highlights the importance of WGS and the challenge of reliable structural variant detection in patients' genetic explorations as well as functional tests to assess a variant's pathogenicity.
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Affiliation(s)
- Adella Karam
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, Institut de Génétique Médicale d’Alsace (IGMA), Faculté de Médecine FMTS, Université de Strasbourg, 67000 Strasbourg, France
| | - Clarisse Delvallée
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, Institut de Génétique Médicale d’Alsace (IGMA), Faculté de Médecine FMTS, Université de Strasbourg, 67000 Strasbourg, France
| | - Alejandro Estrada-Cuzcano
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, Institut de Génétique Médicale d’Alsace (IGMA), Faculté de Médecine FMTS, Université de Strasbourg, 67000 Strasbourg, France
| | - Véronique Geoffroy
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, Institut de Génétique Médicale d’Alsace (IGMA), Faculté de Médecine FMTS, Université de Strasbourg, 67000 Strasbourg, France
| | - Jean-Baptiste Lamouche
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, Institut de Génétique Médicale d’Alsace (IGMA), Faculté de Médecine FMTS, Université de Strasbourg, 67000 Strasbourg, France
| | - Anne-Sophie Leuvrey
- Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France (E.N.)
| | - Elsa Nourisson
- Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France (E.N.)
| | - Julien Tarabeux
- Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France (E.N.)
| | - Corinne Stoetzel
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, Institut de Génétique Médicale d’Alsace (IGMA), Faculté de Médecine FMTS, Université de Strasbourg, 67000 Strasbourg, France
| | - Sophie Scheidecker
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, Institut de Génétique Médicale d’Alsace (IGMA), Faculté de Médecine FMTS, Université de Strasbourg, 67000 Strasbourg, France
- Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France (E.N.)
| | - Louise Frances Porter
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, Institut de Génétique Médicale d’Alsace (IGMA), Faculté de Médecine FMTS, Université de Strasbourg, 67000 Strasbourg, France
- Centre de Référence Pour les Affections Rares en Génétique Ophtalmologique (CARGO), Institut de Génétique Médicale d’Alsace (IGMA), Filière SENSGENE, Hôpitaux Universitaires de Strasbourg, 67091 Strasbourg, France
| | - Emmanuelle Génin
- Inserm, Université de Brest, EFS, UMR 1078, GGB, F-29200 Brest, France
| | - Richard Redon
- CHU Nantes, CNRS, INSERM, L’institut du Thorax, Nantes Université, 44000 Nantes, France
| | - Florian Sandron
- CEA, Centre National de Recherche en Génomique Humaine, Université Paris-Saclay, 91057 Evry, France
| | - Anne Boland
- CEA, Centre National de Recherche en Génomique Humaine, Université Paris-Saclay, 91057 Evry, France
| | - Jean-François Deleuze
- CEA, Centre National de Recherche en Génomique Humaine, Université Paris-Saclay, 91057 Evry, France
| | - Nicolas Le May
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, Institut de Génétique Médicale d’Alsace (IGMA), Faculté de Médecine FMTS, Université de Strasbourg, 67000 Strasbourg, France
| | - Hélène Dollfus
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, Institut de Génétique Médicale d’Alsace (IGMA), Faculté de Médecine FMTS, Université de Strasbourg, 67000 Strasbourg, France
- Centre de Référence Pour les Affections Rares en Génétique Ophtalmologique (CARGO), Institut de Génétique Médicale d’Alsace (IGMA), Filière SENSGENE, Hôpitaux Universitaires de Strasbourg, 67091 Strasbourg, France
- Service de Génétique Médicale, Institut de Génétique Médicale d’Alsace (IGMA), Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France
| | - Jean Muller
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, Institut de Génétique Médicale d’Alsace (IGMA), Faculté de Médecine FMTS, Université de Strasbourg, 67000 Strasbourg, France
- Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France (E.N.)
- Unité Fonctionnelle de Bioinformatique Médicale Appliquée au Diagnostic (UF7363), Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France
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14
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Ewerling A, Maissl V, Wickstead B, May-Simera HL. Neofunctionalization of ciliary BBS proteins to nuclear roles is likely a frequent innovation across eukaryotes. iScience 2023; 26:106410. [PMID: 37034981 PMCID: PMC10074162 DOI: 10.1016/j.isci.2023.106410] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 07/20/2022] [Accepted: 03/10/2023] [Indexed: 03/17/2023] Open
Abstract
The eukaryotic BBSome is a transport complex within cilia and assembled by chaperonin-like BBS proteins. Recent work indicates nuclear functions for BBS proteins in mammals, but it is unclear how common these are in extant proteins or when they evolved. We screened for BBS orthologues across a diverse set of eukaryotes, consolidated nuclear association via signal sequence predictions and permutation analysis, and validated nuclear localization in mammalian cells via fractionation and immunocytochemistry. BBS proteins are-with exceptions-conserved as a set in ciliated species. Predictions highlight five most likely nuclear proteins and suggest that nuclear roles evolved independently of nuclear access during mitosis. Nuclear localization was confirmed in human cells. These findings suggest that nuclear BBS functions are potentially not restricted to mammals, but may be a common frequently co-opted eukaryotic feature. Understanding the functional spectrum of BBS proteins will help elucidating their role in gene regulation, development, and disease.
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Affiliation(s)
- Alexander Ewerling
- Institute of Molecular Physiology, Faculty of Biology, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Vanessa Maissl
- Institute of Molecular Physiology, Faculty of Biology, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Bill Wickstead
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Helen Louise May-Simera
- Institute of Molecular Physiology, Faculty of Biology, Johannes Gutenberg-University Mainz, Mainz, Germany
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15
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Zare Ashrafi F, Akhtarkhavari T, Fattahi Z, Asadnezhad M, Beheshtian M, Arzhangi S, Najmabadi H, Kahrizi K. Emerging Epidemiological Data on Rare Intellectual Disability Syndromes from Analyzing the Data of a Large Iranian Cohort. ARCHIVES OF IRANIAN MEDICINE 2023; 26:186-197. [PMID: 38301078 PMCID: PMC10685746 DOI: 10.34172/aim.2023.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 02/25/2023] [Indexed: 02/03/2024]
Abstract
BACKGROUND Intellectual disability (ID) is a genetically heterogeneous condition, and so far, 1679 human genes have been identified for this phenotype. Countries with a high rate of parental consanguinity, such as Iran, provide an excellent opportunity to identify the remaining novel ID genes, especially those with an autosomal recessive (AR) mode of inheritance. This study aimed to investigate the most prevalent ID genes identified via next-generation sequencing (NGS) in a large ID cohort at the Genetics Research Center (GRC) of the University of Social Welfare and Rehabilitation Sciences. METHODS First, we surveyed the epidemiological data of 619 of 1295 families in our ID cohort, who referred to the Genetics Research Center from all over the country between 2004 and 2021 for genetic investigation via the NGS pipeline. We then compared our data with those of several prominent studies conducted in consanguineous countries. Data analysis, including cohort data extraction, categorization, and comparison, was performed using the R program version 4.1.2. RESULTS We categorized the most common ID genes that were mutated in more than two families into 17 categories. The most common syndromic ID in our cohort was AP4 deficiency syndrome, and the most common non-syndromic autosomal recessive intellectual disability (ARID) gene was ASPM. We identified two unrelated families for the 36 ID genes. We found 14 genes in common between our cohort and the Arab and Pakistani groups, of which three genes (AP4M1, AP4S1, and ADGRG1) were repeated more than once. CONCLUSION To date, there has been no comprehensive targeted NGS platform for the detection of ID genes in our country. Due to the large sample size of our study, our data may provide the initial step toward designing an indigenously targeted NGS platform for the diagnosis of ID, especially common ARID in our population.
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Affiliation(s)
- Farzane Zare Ashrafi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Tara Akhtarkhavari
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Zohreh Fattahi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Maryam Asadnezhad
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Maryam Beheshtian
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Sanaz Arzhangi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Hossein Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Kimia Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
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16
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Chiuso F, Delle Donne R, Giamundo G, Rinaldi L, Borzacchiello D, Moraca F, Intartaglia D, Iannucci R, Senatore E, Lignitto L, Garbi C, Conflitti P, Catalanotti B, Conte I, Feliciello A. Ubiquitylation of BBSome is required for ciliary assembly and signaling. EMBO Rep 2023; 24:e55571. [PMID: 36744302 PMCID: PMC10074118 DOI: 10.15252/embr.202255571] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 12/27/2022] [Accepted: 01/17/2023] [Indexed: 02/07/2023] Open
Abstract
Bardet-Biedl syndrome (BBS) is a ciliopathy characterized by retinal degeneration, obesity, renal abnormalities, postaxial polydactyly, and developmental defects. Genes mutated in BBS encode for components and regulators of the BBSome, an octameric complex that controls the trafficking of cargos and receptors within the primary cilium. Although both structure and function of the BBSome have been extensively studied, the impact of ubiquitin signaling on BBSome is largely unknown. We identify the E3 ubiquitin ligase PJA2 as a novel resident of the ciliary compartment and regulator of the BBSome. Upon GPCR-cAMP stimulation, PJA2 ubiquitylates BBSome subunits. We demonstrate that ubiquitylation of BBS1 at lysine 143 increases the stability of the BBSome and promotes its binding to BBS3, an Arf-like GTPase protein controlling the targeting of the BBSome to the ciliary membrane. Downregulation of PJA2 or expression of a ubiquitylation-defective BBS1 mutant (BBS1K143R ) affects the trafficking of G-protein-coupled receptors (GPCRs) and Shh-dependent gene transcription. Expression of BBS1K143R in vivo impairs cilium formation, embryonic development, and photoreceptors' morphogenesis, thus recapitulating the BBS phenotype in the medaka fish model.
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Affiliation(s)
- Francesco Chiuso
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Rossella Delle Donne
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Giuliana Giamundo
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Department of Biology, University of Naples Federico II, Naples, Italy
| | - Laura Rinaldi
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Domenica Borzacchiello
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Federica Moraca
- Department of Pharmacy, University of Naples "Federico II", Naples, Italy.,Net4Science srl, University "Magna Graecia" of Catanzaro, Catanzaro, Italy
| | | | - Rosa Iannucci
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Emanuela Senatore
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Luca Lignitto
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy.,Cancer Research Center of Marseille (CRCM), CNRS, Aix Marseille Univ, INSERM, Institut Paoli-Calmettes, Marseille, France
| | - Corrado Garbi
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Paolo Conflitti
- Faculty of Biomedical Sciences, Institute of Computational Science, Università della Svizzera Italiana (USI), Lugano, Switzerland
| | - Bruno Catalanotti
- Department of Pharmacy, University of Naples "Federico II", Naples, Italy
| | - Ivan Conte
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Department of Biology, University of Naples Federico II, Naples, Italy
| | - Antonio Feliciello
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
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17
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Meleppattu S, Zhou H, Dai J, Gui M, Brown A. Mechanism of IFT-A polymerization into trains for ciliary transport. Cell 2022; 185:4986-4998.e12. [PMID: 36563665 PMCID: PMC9794116 DOI: 10.1016/j.cell.2022.11.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/14/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022]
Abstract
Intraflagellar transport (IFT) is the highly conserved process by which proteins are transported along ciliary microtubules by a train-like polymeric assembly of IFT-A and IFT-B complexes. IFT-A is sandwiched between IFT-B and the ciliary membrane, consistent with its putative role in transporting transmembrane and membrane-associated cargoes. Here, we have used single-particle analysis electron cryomicroscopy (cryo-EM) to determine structures of native IFT-A complexes. We show that subcomplex rearrangements enable IFT-A to polymerize laterally on anterograde IFT trains, revealing a cooperative assembly mechanism. Surprisingly, we discover that binding of IFT-A to IFT-B shields the preferred lipid-binding interface from the ciliary membrane but orients an interconnected network of β-propeller domains with the capacity to accommodate diverse cargoes toward the ciliary membrane. This work provides a mechanistic basis for understanding IFT-train assembly and cargo interactions.
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Affiliation(s)
- Shimi Meleppattu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Haixia Zhou
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Jin Dai
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Miao Gui
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Alan Brown
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
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18
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Abstract
The assembly and maintenance of most cilia and eukaryotic flagella depends on intraflagellar transport (IFT), the bidirectional movement of multi-megadalton IFT trains along the axonemal microtubules. These IFT trains function as carriers, moving ciliary proteins between the cell body and the organelle. Whereas tubulin, the principal protein of cilia, binds directly to IFT particle proteins, the transport of other ciliary proteins and complexes requires adapters that link them to the trains. Large axonemal substructures, such as radial spokes, outer dynein arms and inner dynein arms, assemble in the cell body before attaching to IFT trains, using the adapters ARMC2, ODA16 and IDA3, respectively. Ciliary import of several membrane proteins involves the putative adapter tubby-like protein 3 (TULP3), whereas membrane protein export involves the BBSome, an octameric complex that co-migrates with IFT particles. Thus, cells employ a variety of adapters, each of which is substoichiometric to the core IFT machinery, to expand the cargo range of the IFT trains. This Review summarizes the individual and shared features of the known cargo adapters and discusses their possible role in regulating the transport capacity of the IFT pathway.
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Affiliation(s)
- Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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19
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Yan X, Shen Y. Rab-like small GTPases in the regulation of ciliary Bardet-Biedl syndrome (BBS) complex transport. FEBS J 2022; 289:7359-7367. [PMID: 34655445 DOI: 10.1111/febs.16232] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/13/2021] [Accepted: 10/15/2021] [Indexed: 01/13/2023]
Abstract
Primary cilia, microtubule-based hair-like structures protruding from most cells, contain membranes enriched in signaling molecules and function as sensory and regulatory organelles critical for development and tissue homeostasis. Intraflagellar transport (IFT), cilia-specific bidirectional transport, is required for the assembly, maintenance, and function of cilia. BBSome, the coat complex, acts as the adaptor between the IFT complex and membrane proteins and is therefore essential for establishing the specific compartmentalization of signaling molecules in the cilia. Recent findings have revealed that three ciliary Rab-like small GTPases, IFT27, IFT22, and Rabl2, play critical regulatory roles in ciliary BBSome transport. In this review, we provide an overview of these three Rab-like small GTPases and their relationship with BBSome.
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Affiliation(s)
- Xiumin Yan
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, China
| | - Yidong Shen
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
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20
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Clupper M, Gill R, Elsayyid M, Touroutine D, Caplan JL, Tanis JE. Kinesin-2 motors differentially impact biogenesis of extracellular vesicle subpopulations shed from sensory cilia. iScience 2022; 25:105262. [PMID: 36304122 PMCID: PMC9593189 DOI: 10.1016/j.isci.2022.105262] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 07/13/2022] [Accepted: 09/26/2022] [Indexed: 01/21/2023] Open
Abstract
Extracellular vesicles (EVs) are bioactive lipid-bilayer enclosed particles released from nearly all cells. One specialized site for EV shedding is the primary cilium. Here, we discover the conserved ion channel CLHM-1 as a ciliary EV cargo. Imaging of EVs released from sensory neuron cilia of Caenorhabditis elegans expressing fluorescently tagged CLHM-1 and TRP polycystin-2 channel PKD-2 shows enrichment of these cargoes in distinct EV subpopulations that are differentially shed in response to mating partner availability. PKD-2 alone is present in EVs shed from the cilium distal tip, whereas CLHM-1 EVs bud from a secondary site(s), including the ciliary base. Heterotrimeric and homodimeric kinesin-2 motors have discrete impacts on PKD-2 and CLHM-1 colocalization in both cilia and EVs. Total loss of kinesin-2 activity decreases shedding of PKD-2 but not CLHM-1 EVs. Our data demonstrate that anterograde intraflagellar transport is required for selective enrichment of protein cargoes into heterogeneous EVs with different signaling potentials.
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Affiliation(s)
- Michael Clupper
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Rachael Gill
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Malek Elsayyid
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Denis Touroutine
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Jeffrey L. Caplan
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE 19716, USA
| | - Jessica E. Tanis
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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21
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Tao T, Liu J, Wang B, Pang J, Li X, Huang L. Novel mutations in BBS genes and clinical characterization of Chinese families with Bardet-Biedl syndrome. Eur J Ophthalmol 2022; 33:11206721221136324. [PMID: 36325687 DOI: 10.1177/11206721221136324] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
PURPOSE Bardet-Biedl syndrome (BBS) is a rare autosomal-recessive inherited disorder characterized by multisystem anomalies. The objective of this study was to detect and analyse pathogenic variants in four Chinese families with BBS. METHODS Comprehensive clinical examinations were performed to investigate and evaluate the phenotypes of the affected individuals from four families. Genomic DNA was extracted from peripheral blood. Next-generation sequencing (NGS) was performed for four families, and the presence of pathogenic variants was confirmed via Sanger sequencing. RESULTS There were two males and three females with a mean age of 16.00 years. All probands displayed the primary clinical features of BBS. Mutation screening demonstrated four novel mutations: c.613C>T; p.Q205* in the BBS5 gene, c.1391C>G; p.S464* in the BBS10 gene, and c.155delC; p.S52* and c.1584T>G; p.Y528* in the BBS12 gene. Two previously reported mutations were also identified, including c.534 + 1G>T in the BBS2 gene and c.539G>A; p.G180E in the BBS10 gene. The bioinformatic analysis revealed that all the detected mutations in BBS genes were disease causing. CONCLUSIONS This study identified four novel BBS gene mutations in these Chinese families and further expanded the genotypic spectrum of BBS, thus contributing to the literature and understanding of this multisystem disease.
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Affiliation(s)
- Tianchang Tao
- Department of Ophthalmology, 71185Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, China
- Department of Ophthalmology, Peking University People's Hospital, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Jia Liu
- Department of Ophthalmology, 71185Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, China
- Department of Ophthalmology, Peking University People's Hospital, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Bin Wang
- Eye Research Institute, 599608Xiamen Eye Center of Xiamen University, Xiamen, China
| | - Jijing Pang
- Eye Research Institute, 599608Xiamen Eye Center of Xiamen University, Xiamen, China
| | - Xiaoxin Li
- Department of Ophthalmology, 71185Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, China
- Department of Ophthalmology, Peking University People's Hospital, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
- Eye Research Institute, 599608Xiamen Eye Center of Xiamen University, Xiamen, China
| | - Lvzhen Huang
- Department of Ophthalmology, 71185Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, China
- Department of Ophthalmology, Peking University People's Hospital, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
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22
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Mayer SK, Thomas J, Helms M, Kothapalli A, Cherascu I, Salesevic A, Stalter E, Wang K, Datta P, Searby C, Seo S, Hsu Y, Bhattarai S, Sheffield VC, Drack AV. Progressive retinal degeneration of rods and cones in a Bardet-Biedl syndrome type 10 mouse model. Dis Model Mech 2022; 15:dmm049473. [PMID: 36125046 PMCID: PMC9536196 DOI: 10.1242/dmm.049473] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 08/03/2022] [Indexed: 11/23/2022] Open
Abstract
Bardet-Biedl syndrome (BBS) is a multi-organ autosomal-recessive disorder caused by mutations in at least 22 different genes. A constant feature is early-onset retinal degeneration leading to blindness. Among the most common forms is BBS type 10 (BBS10), which is caused by mutations in a gene encoding a chaperonin-like protein. To aid in developing treatments, we phenotyped a Bbs10 knockout (Bbs10-/-) mouse model. Analysis by optical coherence tomography (OCT), electroretinography (ERG) and a visually guided swim assay (VGSA) revealed a progressive degeneration (from P19 to 8 months of age) of the outer nuclear layer that is visible by OCT and histology. Cone ERG was absent from at least P30, at which time rod ERG was reduced to 74.4% of control levels; at 8 months, rod ERG was 2.3% of that of controls. VGSA demonstrated loss of functional vision at 9 months. These phenotypes progressed more rapidly than retinal degeneration in the Bbs1M390R/M390R knock-in mouse. This study defines endpoints for preclinical trials that can be utilized to detect a treatment effect in the Bbs10-/- mouse and extrapolated to human clinical trials.
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Affiliation(s)
- Sara K. Mayer
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Jacintha Thomas
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Megan Helms
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Aishwarya Kothapalli
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Ioana Cherascu
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Adisa Salesevic
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Elliot Stalter
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Kai Wang
- Department of Biostatistics, University of Iowa, Iowa City, IA 52242, USA
| | - Poppy Datta
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Charles Searby
- Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Ying Hsu
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Sajag Bhattarai
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Val C. Sheffield
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
- Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
| | - Arlene V. Drack
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
- Department of Ophthalmology and Visual Sciences, Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
- Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
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23
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Dai J, Zhang G, Alkhofash RA, Mekonnen B, Saravanan S, Xue B, Fan ZC, Betleja E, Cole DG, Liu P, Lechtreck K. Loss of ARL13 impedes BBSome-dependent cargo export from Chlamydomonas cilia. J Cell Biol 2022; 221:213429. [PMID: 36040375 PMCID: PMC9436004 DOI: 10.1083/jcb.202201050] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 05/12/2022] [Accepted: 07/11/2022] [Indexed: 12/25/2022] Open
Abstract
The GTPase Arl13b participates in ciliary protein transport, but its contribution to intraflagellar transport (IFT), the main motor-based protein shuttle of cilia, remains largely unknown. Chlamydomonas arl13 mutant cilia were characterized by both abnormal reduction and accumulation of select membrane-associated proteins. With respect to the latter, a similar set of proteins including phospholipase D (PLD) also accumulated in BBSome-deficient cilia. IFT and BBSome traffic were apparently normal in arl13. However, transport of PLD, which in control cells moves by BBSome-dependent IFT, was impaired in arl13, causing PLD to accumulate in cilia. ARL13 only rarely and transiently traveled by IFT, indicating that it is not a co-migrating adapter securing PLD to IFT trains. In conclusion, the loss of Chlamydomonas ARL13 impedes BBSome-dependent protein transport, resulting in overlapping biochemical defects in arl13 and bbs mutant cilia.
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Affiliation(s)
- Jin Dai
- Cellular Biology, University of Georgia, Athens, GA
| | - Gui Zhang
- Cellular Biology, University of Georgia, Athens, GA
| | | | | | | | - Bin Xue
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Zhen-Chuan Fan
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | | | | | - Peiwei Liu
- College of Life Science, Shandong Normal University, Jinan, Shandong, China
| | - Karl Lechtreck
- Cellular Biology, University of Georgia, Athens, GA,Correspondence to Karl F. Lechtreck:
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24
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Schmidt S, Luecken MD, Trümbach D, Hembach S, Niedermeier KM, Wenck N, Pflügler K, Stautner C, Böttcher A, Lickert H, Ramirez-Suastegui C, Ahmad R, Ziller MJ, Fitzgerald JC, Ruf V, van de Berg WDJ, Jonker AJ, Gasser T, Winner B, Winkler J, Vogt Weisenhorn DM, Giesert F, Theis FJ, Wurst W. Primary cilia and SHH signaling impairments in human and mouse models of Parkinson's disease. Nat Commun 2022; 13:4819. [PMID: 35974013 PMCID: PMC9380673 DOI: 10.1038/s41467-022-32229-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 07/21/2022] [Indexed: 12/13/2022] Open
Abstract
Parkinson’s disease (PD) as a progressive neurodegenerative disorder arises from multiple genetic and environmental factors. However, underlying pathological mechanisms remain poorly understood. Using multiplexed single-cell transcriptomics, we analyze human neural precursor cells (hNPCs) from sporadic PD (sPD) patients. Alterations in gene expression appear in pathways related to primary cilia (PC). Accordingly, in these hiPSC-derived hNPCs and neurons, we observe a shortening of PC. Additionally, we detect a shortening of PC in PINK1-deficient human cellular and mouse models of familial PD. Furthermore, in sPD models, the shortening of PC is accompanied by increased Sonic Hedgehog (SHH) signal transduction. Inhibition of this pathway rescues the alterations in PC morphology and mitochondrial dysfunction. Thus, increased SHH activity due to ciliary dysfunction may be required for the development of pathoetiological phenotypes observed in sPD like mitochondrial dysfunction. Inhibiting overactive SHH signaling may be a potential neuroprotective therapy for sPD. Here, the authors reveal using single-cell RNA sequencing that Parkinson’s disease (PD) patient-derived neuronal cells show altered primary cilia morphology and signaling suggesting cilia dysfunction may underlie PD pathogenesis.
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Affiliation(s)
- Sebastian Schmidt
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Chair of Developmental Genetics, Munich School of Life Sciences Weihenstephan, Technical University of Munich, Alte Akademie 8, 85354, Freising, Germany
| | - Malte D Luecken
- Institute of Computational Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Dietrich Trümbach
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Institute of Metabolism and Cell Death, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Sina Hembach
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Chair of Developmental Genetics, Munich School of Life Sciences Weihenstephan, Technical University of Munich, Alte Akademie 8, 85354, Freising, Germany
| | - Kristina M Niedermeier
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Chair of Developmental Genetics, Munich School of Life Sciences Weihenstephan, Technical University of Munich, Alte Akademie 8, 85354, Freising, Germany
| | - Nicole Wenck
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Chair of Developmental Genetics, Munich School of Life Sciences Weihenstephan, Technical University of Munich, Alte Akademie 8, 85354, Freising, Germany
| | - Klaus Pflügler
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Chair of Developmental Genetics, Munich School of Life Sciences Weihenstephan, Technical University of Munich, Alte Akademie 8, 85354, Freising, Germany
| | - Constantin Stautner
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Chair of Developmental Genetics, Munich School of Life Sciences Weihenstephan, Technical University of Munich, Alte Akademie 8, 85354, Freising, Germany
| | - Anika Böttcher
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Heiko Lickert
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Ciro Ramirez-Suastegui
- Institute of Computational Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Ruhel Ahmad
- Max Planck Institute of Psychiatry, Munich, 80804, Germany
| | - Michael J Ziller
- Department of Psychiatry, University of Münster, 48149, Münster, Germany
| | - Julia C Fitzgerald
- Department of Neurodegenerative Diseases, Center of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - Viktoria Ruf
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-Universität Munich, Feodor-Lynen-Str. 23, 81377, Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Wilma D J van de Berg
- Section Clinical Neuroanatomy and Biobanking (CNAB), Department of Anatomy and Neurosciences, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081HV, Amsterdam, The Netherlands
| | - Allert J Jonker
- Section Clinical Neuroanatomy and Biobanking (CNAB), Department of Anatomy and Neurosciences, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081HV, Amsterdam, The Netherlands
| | - Thomas Gasser
- Department of Neurodegenerative Diseases, Center of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - Beate Winner
- Department of Stem Cell Biology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Glückstrasse 6, 91054, Erlangen, Germany
| | - Jürgen Winkler
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 6, 91054, Erlangen, Germany
| | - Daniela M Vogt Weisenhorn
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Chair of Developmental Genetics, Munich School of Life Sciences Weihenstephan, Technical University of Munich, Alte Akademie 8, 85354, Freising, Germany
| | - Florian Giesert
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.
| | - Fabian J Theis
- Institute of Computational Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany. .,Department of Mathematics, Technische Universität München, Boltzmannstraße 3, 85748, Garching bei München, Germany.
| | - Wolfgang Wurst
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany. .,Chair of Developmental Genetics, Munich School of Life Sciences Weihenstephan, Technical University of Munich, Alte Akademie 8, 85354, Freising, Germany. .,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany. .,German Center for Neurodegenerative Diseases (DZNE) site Munich, Feodor-Lynen-Straße 17, 81377, Munich, Germany.
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25
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Bhardwaj A, Yadav A, Yadav M, Tanwar M. Genetic dissection of non-syndromic retinitis pigmentosa. Indian J Ophthalmol 2022; 70:2355-2385. [PMID: 35791117 PMCID: PMC9426071 DOI: 10.4103/ijo.ijo_46_22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Retinitis pigmentosa (RP) belongs to a group of pigmentary retinopathies. It is the most common form of inherited retinal dystrophy, characterized by progressive degradation of photoreceptors that leads to nyctalopia, and ultimately, complete vision loss. RP is distinguished by the continuous retinal degeneration that progresses from the mid-periphery to the central and peripheral retina. RP was first described and named by Franciscus Cornelius Donders in the year 1857. It is one of the leading causes of bilateral blindness in adults, with an incidence of 1 in 3000 people worldwide. In this review, we are going to focus on the genetic heterogeneity of this disease, which is provided by various inheritance patterns, numerosity of variations and inter-/intra-familial variations based upon penetrance and expressivity. Although over 90 genes have been identified in RP patients, the genetic cause of approximately 50% of RP cases remains unknown. Heterogeneity of RP makes it an extremely complicated ocular impairment. It is so complicated that it is known as “fever of unknown origin”. For prognosis and proper management of the disease, it is necessary to understand its genetic heterogeneity so that each phenotype related to the various genetic variations could be treated.
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Affiliation(s)
- Aarti Bhardwaj
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Anshu Yadav
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Manoj Yadav
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Mukesh Tanwar
- Department of Genetics, M. D. University, Rohtak, Haryana, India
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26
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Long F, Zhang Z, Chen J, Yang S, Tian Y, Mei C, Zhang W, Zan L, Tong B, Cheng G. The role of BBS2 in regulating adipogenesis and the association of its sequence variants with meat quality in Qinchuan cattle. Genomics 2022; 114:110416. [PMID: 35718089 DOI: 10.1016/j.ygeno.2022.110416] [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: 12/28/2021] [Revised: 05/11/2022] [Accepted: 06/13/2022] [Indexed: 11/04/2022]
Abstract
The BBS2 gene plays a vital role in human obesity and fat deposition. However, little is known about it in beef cattle. Therefore, this study investigates the function of BBS2 in the fat deposition of beef cattle and screens the effective SNPs marker for meat quality traits in cattle breeding. The expression of BBS2 is negatively correlated with marbling ratios of beef cattle. Moreover, the knockdown of BBS2 promoted adipogenesis and lipid accumulation of bovine preadipocytes by stimulating PPARγ, FABP4, and FASN expression (P < 0.01). Four novel SNPs in the exons of BBS2 in Chinese Qinchuan cattle were identified and of which the g.24226239C > T (Q527), g.24223562G > A (V441I), and g.24227851A > G (Q627R) were significantly associated with the meat quality of Qinchuan cattle (P < 0.01, P < 0.05). The findings suggested that BBS2 could be used as a candidate gene for meat quality improvement in Qinchuan cattle. Furthermore, these genotypes can be exploited as molecular markers in future beef breeding projects.
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Affiliation(s)
- Feng Long
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Ziyi Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Jiayue Chen
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Sen Yang
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Yuan Tian
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Chugang Mei
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Wenzhen Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Linsen Zan
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China; National Beef Cattle Improvement Centre, Yangling 712100, China
| | - Bin Tong
- The State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China.
| | - Gong Cheng
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China; National Beef Cattle Improvement Centre, Yangling 712100, China.
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27
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Chen X, Shi Z, Yang F, Zhou T, Xie S. Deciphering cilia and ciliopathies using proteomic approaches. FEBS J 2022; 290:2590-2603. [PMID: 35633520 DOI: 10.1111/febs.16538] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/21/2022] [Accepted: 05/19/2022] [Indexed: 12/01/2022]
Abstract
Cilia are microtubule-based organelles that protrude from the cell surface and play crucial roles in cellular signaling pathways and extracellular fluid movement. Defects in the ciliary structures and functions are implicated in a set of hereditary disorders, including polycystic kidney disease, nephronophthisis, and Bardet-Biedl syndrome, which are collectively termed as ciliopathies. The application of mass spectrometry-based proteomic approaches to explore ciliary components provides important clues for understanding their physiological and pathological roles. In this review, we focus primarily on proteomic studies involving the identification of proteins in motile cilia and primary cilia, proteomes in ciliopathies, and interactomes of ciliopathy proteins. Collectively, the integration of these data sets will be beneficial for the comprehensive understanding of ciliary structures and exploring potential biomarkers and therapeutic targets for ciliopathies.
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Affiliation(s)
- Xiying Chen
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China.,Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhouyuanjing Shi
- Department of Gastroenterology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Feng Yang
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China.,Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Tianhua Zhou
- Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Shanshan Xie
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China.,Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
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28
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Loss of the Bardet-Biedl protein Bbs1 alters photoreceptor outer segment protein and lipid composition. Nat Commun 2022; 13:1282. [PMID: 35277505 PMCID: PMC8917222 DOI: 10.1038/s41467-022-28982-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 02/23/2022] [Indexed: 12/22/2022] Open
Abstract
Primary cilia are key sensory organelles whose dysfunction leads to ciliopathy disorders such as Bardet-Biedl syndrome (BBS). Retinal degeneration is common in ciliopathies, since the outer segments (OSs) of photoreceptors are highly specialized primary cilia. BBS1, encoded by the most commonly mutated BBS-associated gene, is part of the BBSome protein complex. Using a bbs1 zebrafish mutant, we show that retinal development and photoreceptor differentiation are unaffected by Bbs1-loss, supported by an initially unaffected transcriptome. Quantitative proteomics and lipidomics on samples enriched for isolated OSs show that Bbs1 is required for BBSome-complex stability and that Bbs1-loss leads to accumulation of membrane-associated proteins in OSs, with enrichment in proteins involved in lipid homeostasis. Disruption of the tightly regulated OS lipid composition with increased OS cholesterol content are paralleled by early functional visual deficits, which precede progressive OS morphological anomalies. Our findings identify a role for Bbs1/BBSome in OS lipid homeostasis, suggesting a pathomechanism underlying retinal degeneration in BBS. Primary cilia are key sensory organelles whose dysfunction leads to ciliopathy disorders such as Bardet-Biedl syndrome (BBS). Here they identify a role for Bbs1 in lipid homeostasis of photoreceptor outer segments in zebrafish, which may contribute to vision loss in patients with Bardet-Biedl syndrome.
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29
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Primary cilia and their effects on immune cell functions and metabolism: a model. Trends Immunol 2022; 43:366-378. [DOI: 10.1016/j.it.2022.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/02/2022] [Accepted: 03/03/2022] [Indexed: 11/21/2022]
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30
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Abstract
Cilia are tail-like organelles responsible for motility, transportation, and sensory functions in eukaryotic cells. Cilia research has been providing multifaceted questions, attracting biologists of various areas and inducing interdisciplinary studies. In this chapter, we mainly focus on efforts to elucidate the molecular mechanism of ciliary beating motion, a field of research that has a long history and is still ongoing. We also overview topics closely related to the motility mechanism, such as ciliogenesis, cilia-related diseases, and sensory cilia. Subnanometer-scale to submillimeter-scale 3D imaging of the axoneme and the basal body resulted in a wide variety of insights into these questions.
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Affiliation(s)
- Takashi Ishikawa
- Department of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland.
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31
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Quidwai T, Wang J, Hall EA, Petriman NA, Leng W, Kiesel P, Wells JN, Murphy LC, Keighren MA, Marsh JA, Lorentzen E, Pigino G, Mill P. A WDR35-dependent coat protein complex transports ciliary membrane cargo vesicles to cilia. eLife 2021; 10:e69786. [PMID: 34734804 PMCID: PMC8754431 DOI: 10.7554/elife.69786] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 11/04/2021] [Indexed: 11/13/2022] Open
Abstract
Intraflagellar transport (IFT) is a highly conserved mechanism for motor-driven transport of cargo within cilia, but how this cargo is selectively transported to cilia is unclear. WDR35/IFT121 is a component of the IFT-A complex best known for its role in ciliary retrograde transport. In the absence of WDR35, small mutant cilia form but fail to enrich in diverse classes of ciliary membrane proteins. In Wdr35 mouse mutants, the non-core IFT-A components are degraded and core components accumulate at the ciliary base. We reveal deep sequence homology of WDR35 and other IFT-A subunits to α and ß' COPI coatomer subunits and demonstrate an accumulation of 'coat-less' vesicles that fail to fuse with Wdr35 mutant cilia. We determine that recombinant non-core IFT-As can bind directly to lipids and provide the first in situ evidence of a novel coat function for WDR35, likely with other IFT-A proteins, in delivering ciliary membrane cargo necessary for cilia elongation.
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Affiliation(s)
- Tooba Quidwai
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Jiaolong Wang
- Department of Molecular Biology and Genetics, Aarhus UniversityAarhusDenmark
| | - Emma A Hall
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Narcis A Petriman
- Department of Molecular Biology and Genetics, Aarhus UniversityAarhusDenmark
| | - Weihua Leng
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
| | - Petra Kiesel
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
| | - Jonathan N Wells
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Laura C Murphy
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Margaret A Keighren
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Joseph A Marsh
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus UniversityAarhusDenmark
| | - Gaia Pigino
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Human TechnopoleMilanItaly
| | - Pleasantine Mill
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
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32
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Valentine M, Van Houten J. Using Paramecium as a Model for Ciliopathies. Genes (Basel) 2021; 12:genes12101493. [PMID: 34680887 PMCID: PMC8535419 DOI: 10.3390/genes12101493] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 01/26/2023] Open
Abstract
Paramecium has served as a model organism for the studies of many aspects of genetics and cell biology: non-Mendelian inheritance, genome duplication, genome rearrangements, and exocytosis, to name a few. However, the large number and patterning of cilia that cover its surface have inspired extraordinary ultrastructural work. Its swimming patterns inspired exquisite electrophysiological studies that led to a description of the bioelectric control of ciliary motion. A genetic dissection of swimming behavior moved the field toward the genes and gene products underlying ciliary function. With the advent of molecular technologies, it became clear that there was not only great conservation of ciliary structure but also of the genes coding for ciliary structure and function. It is this conservation and the legacy of past research that allow us to use Paramecium as a model for cilia and ciliary diseases called ciliopathies. However, there would be no compelling reason to study Paramecium as this model if there were no new insights into cilia and ciliopathies to be gained. In this review, we present studies that we believe will do this. For example, while the literature continues to state that immotile cilia are sensory and motile cilia are not, we will provide evidence that Paramecium cilia are clearly sensory. Other examples show that while a Paramecium protein is highly conserved it takes a different interacting partner or conducts a different ion than expected. Perhaps these exceptions will provoke new ideas about mammalian systems.
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Affiliation(s)
- Megan Valentine
- State University of New York at Plattsburgh, 101 Broad Street, Plattsburgh, NY 12901, USA;
| | - Judith Van Houten
- Department of Biology, University of Vermont, 120 Marsh Life Science, 109 Carrigan Drive, Burlington, VT 05405, USA
- Correspondence:
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Wensel TG, Potter VL, Moye A, Zhang Z, Robichaux MA. Structure and dynamics of photoreceptor sensory cilia. Pflugers Arch 2021; 473:1517-1537. [PMID: 34050409 PMCID: PMC11216635 DOI: 10.1007/s00424-021-02564-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 02/06/2023]
Abstract
The rod and cone photoreceptor cells of the vertebrate retina have highly specialized structures that enable them to carry out their function of light detection over a broad range of illumination intensities with optimized spatial and temporal resolution. Most prominent are their unusually large sensory cilia, consisting of outer segments packed with photosensitive disc membranes, a connecting cilium with many features reminiscent of the primary cilium transition zone, and a pair of centrioles forming a basal body which serves as the platform upon which the ciliary axoneme is assembled. These structures form a highway through which an enormous flux of material moves on a daily basis to sustain the continual turnover of outer segment discs and the energetic demands of phototransduction. After decades of study, the details of the fine structure and distribution of molecular components of these structures are still incompletely understood, but recent advances in cellular imaging techniques and animal models of inherited ciliary defects are yielding important new insights. This knowledge informs our understanding both of the mechanisms of trafficking and assembly and of the pathophysiological mechanisms of human blinding ciliopathies.
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Affiliation(s)
- Theodore G Wensel
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology and Developmental Biology Graduate Program, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Valencia L Potter
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology and Developmental Biology Graduate Program, Baylor College of Medicine, Houston, TX, 77030, USA
- Medical Scientist Training Program (MSTP), Baylor College of Medicine, Houston, TX, 77030, USA
| | - Abigail Moye
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Zhixian Zhang
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Michael A Robichaux
- Departments of Ophthalmology and Biochemistry, West Virginia University, Morgantown, WV, USA
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Bardet-Biedl Syndrome-Multiple Kaleidoscope Images: Insight into Mechanisms of Genotype-Phenotype Correlations. Genes (Basel) 2021; 12:genes12091353. [PMID: 34573333 PMCID: PMC8465569 DOI: 10.3390/genes12091353] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/22/2021] [Accepted: 08/27/2021] [Indexed: 01/04/2023] Open
Abstract
Bardet-Biedl Syndrome is a rare non-motile primary ciliopathy with multisystem involvement and autosomal recessive inheritance. The clinical picture is extremely polymorphic. The main clinical features are retinal cone-rod dystrophy, central obesity, postaxial polydactyly, cognitive impairment, hypogonadism and genitourinary abnormalities, and kidney disease. It is caused by various types of mutations, mainly in genes encoding BBSome proteins, chaperonins, and IFT complex. Variable expressivity and pleiotropy are correlated with the existence of multiple genes and variants modifiers. This review is focused on the phenomena of heterogeneity (locus, allelic, mutational, and clinical) in Bardet-Biedl Syndrome, its mechanisms, and importance in early diagnosis and proper management.
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Abstract
The intraflagellar transport (IFT) system is a remarkable molecular machine used by cells to assemble and maintain the cilium, a long organelle extending from eukaryotic cells that gives rise to motility, sensing and signaling. IFT plays a critical role in building the cilium by shuttling structural components and signaling receptors between the ciliary base and tip. To provide effective transport, IFT-A and IFT-B adaptor protein complexes assemble into highly repetitive polymers, called IFT trains, that are powered by the motors kinesin-2 and IFT-dynein to move bidirectionally along the microtubules. This dynamic system must be precisely regulated to shuttle different cargo proteins between the ciliary tip and base. In this Cell Science at a Glance article and the accompanying poster, we discuss the current structural and mechanistic understanding of IFT trains and how they function as macromolecular machines to assemble the structure of the cilium.
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Affiliation(s)
- Mareike A Jordan
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Gaia Pigino
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Pfotenhauerstraße 108, 01307 Dresden, Germany.,Human Technopole, Via Cristina Belgioioso 171, 20157 Milan, Italy
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HTR6 and SSTR3 targeting to primary cilia. Biochem Soc Trans 2021; 49:79-91. [PMID: 33599752 DOI: 10.1042/bst20191005] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 12/25/2020] [Accepted: 01/20/2021] [Indexed: 12/30/2022]
Abstract
Primary cilia are hair-like projections of the cell membrane supported by an inner microtubule scaffold, the axoneme, which polymerizes out of a membrane-docked centriole at the ciliary base. By working as specialized signaling compartments, primary cilia provide an optimal environment for many G protein-coupled receptors (GPCRs) and their effectors to efficiently transmit their signals to the rest of the cell. For this to occur, however, all necessary receptors and signal transducers must first accumulate at the ciliary membrane. Serotonin receptor 6 (HTR6) and Somatostatin receptor 3 (SSTR3) are two GPCRs whose signaling in brain neuronal cilia affects cognition and is implicated in psychiatric, neurodegenerative, and oncologic diseases. Over a decade ago, the third intracellular loops (IC3s) of HTR6 and SSTR3 were shown to contain ciliary localization sequences (CLSs) that, when grafted onto non-ciliary GPCRs, could drive their ciliary accumulation. Nevertheless, these CLSs were dispensable for ciliary targeting of HTR6 and SSTR3, suggesting the presence of additional CLSs, which we have recently identified in their C-terminal tails. Herein, we review the discovery and mapping of these CLSs, as well as the state of the art regarding how these CLSs may orchestrate ciliary accumulation of these GPCRs by controlling when and where they interact with the ciliary entry and exit machinery via adaptors such as TULP3, RABL2 and the BBSome.
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Liu YX, Xue B, Sun WY, Wingfield JL, Sun J, Wu M, Lechtreck KF, Wu Z, Fan ZC. Bardet-Biedl syndrome 3 protein promotes ciliary exit of the signaling protein phospholipase D via the BBSome. eLife 2021; 10:59119. [PMID: 33587040 PMCID: PMC7963478 DOI: 10.7554/elife.59119] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 02/13/2021] [Indexed: 12/13/2022] Open
Abstract
Certain ciliary signaling proteins couple with the BBSome, a conserved complex of Bardet–Biedl syndrome (BBS) proteins, to load onto retrograde intraflagellar transport (IFT) trains for their removal out of cilia in Chlamydomonas reinhardtii. Here, we show that loss of the Arf-like 6 (ARL6) GTPase BBS3 causes the signaling protein phospholipase D (PLD) to accumulate in cilia. Upon targeting to the basal body, BBSomes enter and cycle through cilia via IFT, while BBS3 in a GTP-bound state separates from BBSomes, associates with the membrane, and translocates from the basal body to cilia by diffusion. Upon arriving at the ciliary tip, GTP-bound BBS3 binds and recruits BBSomes to the ciliary membrane for interacting with PLD, thus making the PLD-laden BBSomes available to load onto retrograde IFT trains for ciliary exit. Therefore, BBS3 promotes PLD exit from cilia via the BBSome, providing a regulatory mechanism for ciliary signaling protein removal out of cilia.
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Affiliation(s)
- Yan-Xia Liu
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Bin Xue
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Wei-Yue Sun
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Jenna L Wingfield
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Jun Sun
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Mingfu Wu
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, United States
| | - Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Zhenlong Wu
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China
| | - Zhen-Chuan Fan
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
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Kositzke A, Fan D, Wang A, Li H, Worth M, Jiang J. Elucidating the protein substrate recognition of O-GlcNAc transferase (OGT) toward O-GlcNAcase (OGA) using a GlcNAc electrophilic probe. Int J Biol Macromol 2021; 169:51-59. [PMID: 33333092 PMCID: PMC7856287 DOI: 10.1016/j.ijbiomac.2020.12.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/06/2020] [Accepted: 12/10/2020] [Indexed: 12/12/2022]
Abstract
The essential human O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) is the sole enzyme responsible for modifying thousands of intracellular proteins with the monosaccharide O-GlcNAc. This unique modification plays crucial roles in human health and disease, but the substrate recognition of OGT remains poorly understood. Intriguingly, the only human enzyme reported to remove this modification, O-GlcNAcase (OGA), is O-GlcNAc modified. Here, we exploited a GlcNAc electrophilic probe (GEP1A) to rapidly screen OGT mutants in a fluorescence assay that can discriminate between altered OGT-sugar and -protein substrate binding to help elucidate the binding mode of OGT toward OGA protein substrate. Since OGT tetratricopeptide repeat (TPR) domain plays a key role in OGT-OGA binding, we screened 30 OGT TPR mutants, which revealed 15 "ladder like" asparagine or aspartate residues spanning TPRs 3-7 and 10-13.5 that affect OGA O-GlcNAcylation. By applying a truncated OGA construct, we found that OGA's N-terminal region or pseudo histone acetyltransferase domain is not required for its O-GlcNAcylation, suggesting OGT functionally interacts with OGA through its catalytic and/or stalk domains. This work represents the first effort to systemically investigate each OGT TPR and our findings will facilitate the development of new strategies to investigate the role of substrate-specific O-GlcNAcylation.
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Affiliation(s)
- Adam Kositzke
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Dacheng Fan
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Ao Wang
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Hao Li
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Matthew Worth
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Jiaoyang Jiang
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA.
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Hsu Y, Seo S, Sheffield VC. Photoreceptor cilia, in contrast to primary cilia, grant entry to a partially assembled BBSome. Hum Mol Genet 2021; 30:87-102. [PMID: 33517424 DOI: 10.1093/hmg/ddaa284] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 11/16/2020] [Accepted: 01/27/2021] [Indexed: 12/26/2022] Open
Abstract
The BBSome is a protein complex consisting of BBS1, BBS2, BBS4, BBS5, BBS7, BBS8, BBS9 and BBS18 that associates with intraflagellar transport complexes and specializes in ciliary trafficking. In primary cilia, ciliary entry requires the fully assembled BBSome as well as the small GTPase, ARL6 (BBS3). Retinal photoreceptors possess specialized cilia. In light of key structural and functional differences between primary and specialized cilia, we examined the principles of BBSome recruitment to photoreceptor cilia. We performed sucrose gradient fractionation using retinal lysates of Bbs2-/-, Bbs7-/-, Bbs8-/- and Bbs3-/- mice to determine the status of BBSome assembly, then determined localization of BBSome components using immunohistochemistry. Surprisingly, we found that a subcomplex of the BBSome containing at least BBS1, BBS5, BBS8 and BBS9 is recruited to cilia in the absence of BBS2 or BBS7. In contrast, a BBSome subcomplex consisting of BBS1, BBS2, BBS5, BBS7 and BBS9 is found in Bbs8-/- retinas and is denied ciliary entry in photoreceptor cells. In addition, the BBSome remains fully assembled in Bbs3-/- retinas and can be recruited to photoreceptor cilia in the absence of BBS3. We compared phenotypic severity of their retinal degeneration phenotypes. These findings demonstrate that unlike primary cilia, photoreceptor cilia admit a partially assembled BBSome meeting specific requirements. In addition, the recruitment of the BBSome to photoreceptor cilia does not require BBS3. These findings indicate that the ciliary entry of the BBSome is subjected to cell-specific regulation, particularly in cells with highly adapted forms of cilia such as photoreceptors.
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Affiliation(s)
- Ying Hsu
- Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - Val C Sheffield
- Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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Webb S, Mukhopadhyay AG, Roberts AJ. Intraflagellar transport trains and motors: Insights from structure. Semin Cell Dev Biol 2020; 107:82-90. [PMID: 32684327 PMCID: PMC7561706 DOI: 10.1016/j.semcdb.2020.05.021] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 05/19/2020] [Accepted: 05/26/2020] [Indexed: 11/17/2022]
Abstract
Intraflagellar transport (IFT) sculpts the proteome of cilia and flagella; the antenna-like organelles found on the surface of virtually all human cell types. By delivering proteins to the growing ciliary tip, recycling turnover products, and selectively transporting signalling molecules, IFT has critical roles in cilia biogenesis, quality control, and signal transduction. IFT involves long polymeric arrays, termed IFT trains, which move to and from the ciliary tip under the power of the microtubule-based motor proteins kinesin-II and dynein-2. Recent top-down and bottom-up structural biology approaches are converging on the molecular architecture of the IFT train machinery. Here we review these studies, with a focus on how kinesin-II and dynein-2 assemble, attach to IFT trains, and undergo precise regulation to mediate bidirectional transport.
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Affiliation(s)
- Stephanie Webb
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London, United Kingdom
| | - Aakash G Mukhopadhyay
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London, United Kingdom
| | - Anthony J Roberts
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London, United Kingdom.
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Yu K, Liu P, Venkatachalam D, Hopkinson BM, Lechtreck KF. The BBSome restricts entry of tagged carbonic anhydrase 6 into the cis-flagellum of Chlamydomonas reinhardtii. PLoS One 2020; 15:e0240887. [PMID: 33119622 PMCID: PMC7595284 DOI: 10.1371/journal.pone.0240887] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/05/2020] [Indexed: 01/12/2023] Open
Abstract
The two flagella of Chlamydomonas reinhardtii are of the same size and structure but display functional differences, which are critical for flagellar steering movements. However, biochemical differences between the two flagella have not been identified. Here, we show that fluorescence protein-tagged carbonic anhydrase 6 (CAH6-mNG) preferentially localizes to the trans-flagellum, which is organized by the older of the two flagella-bearing basal bodies. The uneven distribution of CAH6-mNG is established early during flagellar assembly and restored after photobleaching, suggesting that it is based on preferred entry or retention of CAH6-mNG in the trans-flagellum. Since CAH6-mNG moves mostly by diffusion, a role of intraflagellar transport (IFT) in establishing its asymmetric distribution is unlikely. Interestingly, CAH6-mNG is present in both flagella of the non-phototactic bardet-biedl syndrome 1 (bbs1) mutant revealing that the BBSome is involved in establishing CAH6-mNG flagellar asymmetry. Using dikaryon rescue experiments, we show that the de novo assembly of CAH6-mNG in flagella is considerably faster than the removal of ectopic CAH6-mNG from bbs flagella. Thus, different rates of flagellar entry of CAH6-mNG rather than its export from flagella is the likely basis for its asymmetric distribution. The data identify a novel role for the C. reinhardtii BBSome in preventing the entry of CAH6-mNG specifically into the cis-flagellum.
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Affiliation(s)
- Kewei Yu
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Peiwei Liu
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Dipna Venkatachalam
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Brian M. Hopkinson
- Department of Marine Sciences, University of Georgia, Athens, Georgia, United States of America
| | - Karl F. Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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Conduit SE, Vanhaesebroeck B. Phosphoinositide lipids in primary cilia biology. Biochem J 2020; 477:3541-3565. [PMID: 32970140 PMCID: PMC7518857 DOI: 10.1042/bcj20200277] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/30/2020] [Accepted: 08/27/2020] [Indexed: 12/11/2022]
Abstract
Primary cilia are solitary signalling organelles projecting from the surface of most cell types. Although the ciliary membrane is continuous with the plasma membrane it exhibits a unique phospholipid composition, a feature essential for normal cilia formation and function. Recent studies have illustrated that distinct phosphoinositide lipid species localise to specific cilia subdomains, and have begun to build a 'phosphoinositide map' of the cilium. The abundance and localisation of phosphoinositides are tightly regulated by the opposing actions of lipid kinases and lipid phosphatases that have also been recently discovered at cilia. The critical role of phosphoinositides in cilia biology is highlighted by the devastating consequences of genetic defects in cilia-associated phosphoinositide regulatory enzymes leading to ciliopathy phenotypes in humans and experimental mouse and zebrafish models. Here we provide a general introduction to primary cilia and the roles phosphoinositides play in cilia biology. In addition to increasing our understanding of fundamental cilia biology, this rapidly expanding field may inform novel approaches to treat ciliopathy syndromes caused by deregulated phosphoinositide metabolism.
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Affiliation(s)
- Sarah E. Conduit
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, U.K
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, U.K
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Petriman NA, Lorentzen E. Structural insights into the architecture and assembly of eukaryotic flagella. MICROBIAL CELL (GRAZ, AUSTRIA) 2020; 7:289-299. [PMID: 33150161 PMCID: PMC7590530 DOI: 10.15698/mic2020.11.734] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/07/2020] [Accepted: 09/14/2020] [Indexed: 12/16/2022]
Abstract
Cilia and flagella are slender projections found on most eukaryotic cells including unicellular organisms such as Chlamydomonas, Trypanosoma and Tetrahymena, where they serve motility and signaling functions. The cilium is a large molecular machine consisting of hundreds of different proteins that are trafficked into the organelle to organize a repetitive microtubule-based axoneme. Several recent studies took advantage of improved cryo-EM methodology to unravel the high-resolution structures of ciliary complexes. These include the recently reported purification and structure determination of axonemal doublet microtubules from the green algae Chlamydomonas reinhardtii, which allows for the modeling of more than 30 associated protein factors to provide deep molecular insight into the architecture and repetitive nature of doublet microtubules. In addition, we will review several recent contributions that dissect the structure and function of ciliary trafficking complexes that ferry structural and signaling components between the cell body and the cilium organelle.
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Affiliation(s)
- Narcis-Adrian Petriman
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, DK-8000 Aarhus C, Denmark
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, DK-8000 Aarhus C, Denmark
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Nechipurenko IV. The Enigmatic Role of Lipids in Cilia Signaling. Front Cell Dev Biol 2020; 8:777. [PMID: 32850869 PMCID: PMC7431879 DOI: 10.3389/fcell.2020.00777] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/24/2020] [Indexed: 12/21/2022] Open
Abstract
Primary cilia are specialized cellular structures that project from the surface of most cell types in metazoans and mediate transduction of major signaling pathways. The ciliary membrane is contiguous with the plasma membrane, yet it exhibits distinct protein and lipid composition, which is essential for ciliary function. Diffusion barriers at the base of a cilium are responsible for establishing unique molecular composition of this organelle. Although considerable progress has been made in identifying mechanisms of ciliary protein trafficking in and out of cilia, it remains largely unknown how the distinct lipid identity of the ciliary membrane is achieved. In this mini review, I summarize recent developments in characterizing lipid composition and organization of the ciliary membrane and discuss the emerging roles of lipids in modulating activity of ciliary signaling components including ion channels and G protein-coupled receptors.
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Affiliation(s)
- Inna V. Nechipurenko
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States
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Prasai A, Schmidt Cernohorska M, Ruppova K, Niederlova V, Andelova M, Draber P, Stepanek O, Huranova M. The BBSome assembly is spatially controlled by BBS1 and BBS4 in human cells. J Biol Chem 2020; 295:14279-14290. [PMID: 32759308 DOI: 10.1074/jbc.ra120.013905] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/04/2020] [Indexed: 12/18/2022] Open
Abstract
Bardet-Biedl syndrome (BBS) is a pleiotropic ciliopathy caused by dysfunction of primary cilia. More than half of BBS patients carry mutations in one of eight genes encoding for subunits of a protein complex, the BBSome, which mediates trafficking of ciliary cargoes. In this study, we elucidated the mechanisms of the BBSome assembly in living cells and how this process is spatially regulated. We generated a large library of human cell lines deficient in a particular BBSome subunit and expressing another subunit tagged with a fluorescent protein. We analyzed these cell lines utilizing biochemical assays, conventional and expansion microscopy, and quantitative fluorescence microscopy techniques: fluorescence recovery after photobleaching and fluorescence correlation spectroscopy. Our data revealed that the BBSome formation is a sequential process. We show that the pre-BBSome is nucleated by BBS4 and assembled at pericentriolar satellites, followed by the translocation of the BBSome into the ciliary base mediated by BBS1. Our results provide a framework for elucidating how BBS-causative mutations interfere with the biogenesis of the BBSome.
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Affiliation(s)
- Avishek Prasai
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Marketa Schmidt Cernohorska
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Klara Ruppova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Veronika Niederlova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Monika Andelova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Draber
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ondrej Stepanek
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martina Huranova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
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Yang S, Bahl K, Chou HT, Woodsmith J, Stelzl U, Walz T, Nachury MV. Near-atomic structures of the BBSome reveal the basis for BBSome activation and binding to GPCR cargoes. eLife 2020; 9:55954. [PMID: 32510327 PMCID: PMC7311171 DOI: 10.7554/elife.55954] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/08/2020] [Indexed: 02/07/2023] Open
Abstract
Dynamic trafficking of G protein-coupled receptors (GPCRs) out of cilia is mediated by the BBSome. In concert with its membrane recruitment factor, the small GTPase ARL6/BBS3, the BBSome ferries GPCRs across the transition zone, a diffusion barrier at the base of cilia. Here, we present the near-atomic structures of the BBSome by itself and in complex with ARL6GTP, and we describe the changes in BBSome conformation induced by ARL6GTP binding. Modeling the interactions of the BBSome with membranes and the GPCR Smoothened (SMO) reveals that SMO, and likely also other GPCR cargoes, must release their amphipathic helix 8 from the membrane to be recognized by the BBSome.
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Affiliation(s)
- Shuang Yang
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, United States
| | - Kriti Bahl
- Department of Ophthalmology, University of California San Francisco, San Francisco, United States
| | - Hui-Ting Chou
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, United States
| | - Jonathan Woodsmith
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz and BioTechMed-Graz, Graz, Austria
| | - Ulrich Stelzl
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz and BioTechMed-Graz, Graz, Austria
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, United States
| | - Maxence V Nachury
- Department of Ophthalmology, University of California San Francisco, San Francisco, United States
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Nakayama K, Katoh Y. Architecture of the IFT ciliary trafficking machinery and interplay between its components. Crit Rev Biochem Mol Biol 2020; 55:179-196. [PMID: 32456460 DOI: 10.1080/10409238.2020.1768206] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cilia and flagella serve as cellular antennae and propellers in various eukaryotic cells, and contain specific receptors and ion channels as well as components of axonemal microtubules and molecular motors to achieve their sensory and motile functions. Not only the bidirectional trafficking of specific proteins within cilia but also their selective entry and exit across the ciliary gate is mediated by the intraflagellar transport (IFT) machinery with the aid of motor proteins. The IFT-B complex, which is powered by the kinesin-2 motor, mediates anterograde protein trafficking from the base to the tip of cilia, whereas the IFT-A complex together with the dynein-2 complex mediates retrograde protein trafficking. The BBSome complex connects ciliary membrane proteins to the IFT machinery. Defects in any component of this trafficking machinery lead to abnormal ciliogenesis and ciliary functions, and results in a broad spectrum of disorders, collectively called the ciliopathies. In this review article, we provide an overview of the architectures of the components of the IFT machinery and their functional interplay in ciliary protein trafficking.
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Affiliation(s)
- Kazuhisa Nakayama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yohei Katoh
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
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48
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Petriman NA, Lorentzen E. Moving proteins along in the cilium. eLife 2020; 9:55254. [PMID: 32052743 PMCID: PMC7018505 DOI: 10.7554/elife.55254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 02/06/2020] [Indexed: 12/11/2022] Open
Abstract
The structures of the bovine and human BBSome reveal that a conformational change is required to recruit the complex to the ciliary membrane.
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Affiliation(s)
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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