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1.
Nat Commun ; 12(1): 612, 2021 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-33504787

RESUMO

The motile cilia of ependymal cells coordinate their beats to facilitate a forceful and directed flow of cerebrospinal fluid (CSF). Each cilium originates from a basal body with a basal foot protruding from one side. A uniform alignment of these basal feet is crucial for the coordination of ciliary beating. The process by which the basal foot originates from subdistal appendages of the basal body, however, is unresolved. Here, we show FGFR1 Oncogene Partner (FOP) is a useful marker for delineating the transformation of a circular, unpolarized subdistal appendage into a polarized structure with a basal foot. Ankyrin repeat and SAM domain-containing protein 1A (ANKS1A) interacts with FOP to assemble region I of the basal foot. Importantly, disruption of ANKS1A reduces the size of region I. This produces an unstable basal foot, which disrupts rotational polarity and the coordinated beating of cilia in young adult mice. ANKS1A deficiency also leads to severe degeneration of the basal foot in aged mice and the detachment of cilia from their basal bodies. This role of ANKS1A in the polarization of the basal foot is evolutionarily conserved in vertebrates. Thus, ANKS1A regulates FOP to build and maintain the polarity of subdistal appendages.


Assuntos
Cílios/metabolismo , Simulação de Dinâmica Molecular , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Envelhecimento/patologia , Animais , Corpos Basais/metabolismo , Evolução Biológica , Cílios/ultraestrutura , Embrião não Mamífero/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ligação Proteica , Fatores de Transcrição/metabolismo , Xenopus/embriologia , Xenopus/metabolismo
2.
Nat Commun ; 12(1): 477, 2021 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-33473120

RESUMO

Axonemal dyneins are tethered to doublet microtubules inside cilia to drive ciliary beating, a process critical for cellular motility and extracellular fluid flow. Axonemal dyneins are evolutionarily and biochemically distinct from cytoplasmic dyneins that transport cargo, and the mechanisms regulating their localization and function are poorly understood. Here, we report a single-particle cryo-EM reconstruction of a three-headed axonemal dynein natively bound to doublet microtubules isolated from cilia. The slanted conformation of the axonemal dynein causes interaction of its motor domains with the neighboring dynein complex. Our structure shows how a heterotrimeric docking complex specifically localizes the linear array of axonemal dyneins to the doublet microtubule by directly interacting with the heavy chains. Our structural analysis establishes the arrangement of conserved heavy, intermediate and light chain subunits, and provides a framework to understand the roles of individual subunits and the interactions between dyneins during ciliary waveform generation.


Assuntos
Dineínas do Axonema/química , Dineínas do Axonema/metabolismo , Microtúbulos/química , Microtúbulos/metabolismo , Movimento Celular , Chlamydomonas reinhardtii , Cílios/metabolismo , Microscopia Crioeletrônica , Citoesqueleto/metabolismo , Flagelos/química , Flagelos/metabolismo , Simulação de Acoplamento Molecular
3.
Nat Commun ; 12(1): 662, 2021 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-33510165

RESUMO

Dynamic assembly and disassembly of primary cilia controls embryonic development and tissue homeostasis. Dysregulation of ciliogenesis causes human developmental diseases termed ciliopathies. Cell-intrinsic regulatory mechanisms of cilia disassembly have been well-studied. The extracellular cues controlling cilia disassembly remain elusive, however. Here, we show that lysophosphatidic acid (LPA), a multifunctional bioactive phospholipid, acts as a physiological extracellular factor to initiate cilia disassembly and promote neurogenesis. Through systematic analysis of serum components, we identify a small molecular-LPA as the major driver of cilia disassembly. Genetic inactivation and pharmacological inhibition of LPA receptor 1 (LPAR1) abrogate cilia disassembly triggered by serum. The LPA-LPAR-G-protein pathway promotes the transcription and phosphorylation of cilia disassembly factors-Aurora A, through activating the transcription coactivators YAP/TAZ and calcium/CaM pathway, respectively. Deletion of Lpar1 in mice causes abnormally elongated cilia and decreased proliferation in neural progenitor cells, thereby resulting in defective neurogenesis. Collectively, our findings establish LPA as a physiological initiator of cilia disassembly and suggest targeting the metabolism of LPA and the LPA pathway as potential therapies for diseases with dysfunctional ciliogenesis.


Assuntos
Cílios/efeitos dos fármacos , Lisofosfolipídeos/farmacologia , Neurogênese/efeitos dos fármacos , Epitélio Pigmentado da Retina/efeitos dos fármacos , Transdução de Sinais , Animais , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Cílios/genética , Cílios/metabolismo , Células HEK293 , Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Humanos , Lisofosfolipídeos/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células-Tronco Neurais/citologia , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/metabolismo , Neurogênese/genética , Ligação Proteica , Interferência de RNA , Receptores de Ácidos Lisofosfatídicos/genética , Receptores de Ácidos Lisofosfatídicos/metabolismo , Epitélio Pigmentado da Retina/citologia , Epitélio Pigmentado da Retina/metabolismo
4.
PLoS Biol ; 18(12): e3001034, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33370260

RESUMO

Cilia play critical roles during embryonic development and adult homeostasis. Dysfunction of cilia leads to various human genetic diseases, including many caused by defects in transition zones (TZs), the "gates" of cilia. The evolutionarily conserved TZ component centrosomal protein 290 (CEP290) is the most frequently mutated human ciliopathy gene, but its roles in ciliogenesis are not completely understood. Here, we report that CEP290 plays an essential role in the initiation of TZ assembly in Drosophila. Mechanistically, the N-terminus of CEP290 directly recruits DAZ interacting zinc finger protein 1 (DZIP1), which then recruits Chibby (CBY) and Rab8 to promote early ciliary membrane formation. Complete deletion of CEP290 blocks ciliogenesis at the initiation stage of TZ assembly, which can be mimicked by DZIP1 deletion mutants. Remarkably, expression of the N-terminus of CEP290 alone restores the TZ localization of DZIP1 and subsequently ameliorates the defects in TZ assembly initiation in cep290 mutants. Our results link CEP290 to DZIP1-CBY/Rab8 module and uncover a previously uncharacterized important function of CEP290 in the coordination of early ciliary membrane formation and TZ assembly.


Assuntos
Cílios/metabolismo , Cílios/fisiologia , Proteínas de Drosophila/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Proteínas de Transporte/metabolismo , Proteínas de Transporte de Cátions/metabolismo , Proteínas de Ciclo Celular/metabolismo , Cílios/genética , Proteínas do Citoesqueleto/metabolismo , Drosophila/metabolismo , Proteínas de Drosophila/fisiologia , GTP Fosfo-Hidrolases/metabolismo , Proteínas Associadas aos Microtúbulos/fisiologia , Proteínas Nucleares/metabolismo
5.
Nat Commun ; 11(1): 5772, 2020 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-33188191

RESUMO

Hypothalamic neurons including proopiomelanocortin (POMC)-producing neurons regulate body weights. The non-motile primary cilium is a critical sensory organelle on the cell surface. An association between ciliary defects and obesity has been suggested, but the underlying mechanisms are not fully understood. Here we show that inhibition of ciliogenesis in POMC-expressing developing hypothalamic neurons, by depleting ciliogenic genes IFT88 and KIF3A, leads to adulthood obesity in mice. In contrast, adult-onset ciliary dysgenesis in POMC neurons causes no significant change in adiposity. In developing POMC neurons, abnormal cilia formation disrupts axonal projections through impaired lysosomal protein degradation. Notably, maternal nutrition and postnatal leptin surge have a profound impact on ciliogenesis in the hypothalamus of neonatal mice; through these effects they critically modulate the organization of hypothalamic feeding circuits. Our findings reveal a mechanism of early life programming of adult adiposity, which is mediated by primary cilia in developing hypothalamic neurons.


Assuntos
Adiposidade , Cílios/metabolismo , Hipotálamo/embriologia , Hipotálamo/metabolismo , Lisossomos/metabolismo , Animais , Animais Recém-Nascidos , Núcleo Arqueado do Hipotálamo/metabolismo , Axônios/metabolismo , Metabolismo Energético , Feminino , Glucose/metabolismo , Leptina/metabolismo , Desnutrição/patologia , Camundongos Endogâmicos C57BL , Proteínas Associadas aos Microtúbulos/metabolismo , Neurogênese , Obesidade/metabolismo , Obesidade/patologia , Organogênese , Pró-Opiomelanocortina/metabolismo , Proteólise
6.
Nat Commun ; 11(1): 5816, 2020 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-33199730

RESUMO

Primary microcephaly (MCPH) is characterized by reduced brain size and intellectual disability. The exact pathophysiological mechanism underlying MCPH remains to be elucidated, but dysfunction of neuronal progenitors in the developing neocortex plays a major role. We identified a homozygous missense mutation (p.W155C) in Ribosomal RNA Processing 7 Homolog A, RRP7A, segregating with MCPH in a consanguineous family with 10 affected individuals. RRP7A is highly expressed in neural stem cells in developing human forebrain, and targeted mutation of Rrp7a leads to defects in neurogenesis and proliferation in a mouse stem cell model. RRP7A localizes to centrosomes, cilia and nucleoli, and patient-derived fibroblasts display defects in ribosomal RNA processing, primary cilia resorption, and cell cycle progression. Analysis of zebrafish embryos supported that the patient mutation in RRP7A causes reduced brain size, impaired neurogenesis and cell proliferation, and defective ribosomal RNA processing. These findings provide novel insight into human brain development and MCPH.


Assuntos
Cílios/metabolismo , Microcefalia/genética , Neurogênese , Biogênese de Organelas , Proteínas de Ligação a RNA/genética , Ribossomos/metabolismo , Adulto , Animais , Sequência de Bases , Encéfalo/embriologia , Encéfalo/patologia , Ciclo Celular , Nucléolo Celular/metabolismo , Centrossomo/metabolismo , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Humanos , Masculino , Camundongos , Mutação/genética , Células-Tronco Neurais/metabolismo , Proteínas Nucleares/metabolismo , Paquistão , Linhagem , Ligação Proteica , Processamento Pós-Transcricional do RNA , RNA Ribossômico/genética , Proteínas de Ligação a RNA/metabolismo , Peixe-Zebra/embriologia
7.
Nat Commun ; 11(1): 5520, 2020 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-33139725

RESUMO

Axonemal dynein ATPases direct ciliary and flagellar beating via adenosine triphosphate (ATP) hydrolysis. The modulatory effect of adenosine monophosphate (AMP) and adenosine diphosphate (ADP) on flagellar beating is not fully understood. Here, we describe a deficiency of cilia and flagella associated protein 45 (CFAP45) in humans and mice that presents a motile ciliopathy featuring situs inversus totalis and asthenospermia. CFAP45-deficient cilia and flagella show normal morphology and axonemal ultrastructure. Proteomic profiling links CFAP45 to an axonemal module including dynein ATPases and adenylate kinase as well as CFAP52, whose mutations cause a similar ciliopathy. CFAP45 binds AMP in vitro, consistent with structural modelling that identifies an AMP-binding interface between CFAP45 and AK8. Microtubule sliding of dyskinetic sperm from Cfap45-/- mice is rescued with the addition of either AMP or ADP with ATP, compared to ATP alone. We propose that CFAP45 supports mammalian ciliary and flagellar beating via an adenine nucleotide homeostasis module.


Assuntos
Nucleotídeos de Adenina/metabolismo , Astenozoospermia/genética , Proteínas do Citoesqueleto/deficiência , Situs Inversus/genética , Adolescente , Adulto , Animais , Astenozoospermia/patologia , Axonema/ultraestrutura , Sistemas CRISPR-Cas/genética , Cílios/metabolismo , Cílios/ultraestrutura , Proteínas do Citoesqueleto/genética , Análise Mutacional de DNA , Modelos Animais de Doenças , Epididimo/patologia , Feminino , Flagelos/metabolismo , Flagelos/ultraestrutura , Humanos , Mutação com Perda de Função , Masculino , Camundongos , Camundongos Knockout , Pessoa de Meia-Idade , Planárias/citologia , Planárias/genética , Planárias/metabolismo , Mucosa Respiratória/citologia , Mucosa Respiratória/patologia , Situs Inversus/diagnóstico por imagem , Situs Inversus/patologia , Motilidade Espermática/genética , Tomografia Computadorizada por Raios X , Sequenciamento Completo do Exoma
8.
Nat Commun ; 11(1): 5312, 2020 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-33082319

RESUMO

Evidence is lacking as to how developing neurons integrate mitogenic signals with microenvironment cues to control proliferation and differentiation. We determine that the Siah2 E3 ubiquitin ligase functions in a coincidence detection circuit linking responses to the Shh mitogen and the extracellular matrix to control cerebellar granule neurons (CGN) GZ occupancy. We show that Shh signaling maintains Siah2 expression in CGN progenitors (GNPs) in a Ras/Mapk-dependent manner. Siah2 supports ciliogenesis in a feed-forward fashion by restraining cilium disassembly. Efforts to identify sources of the Ras/Mapk signaling led us to discover that GNPs respond to laminin, but not vitronectin, in the GZ microenvironment via integrin ß1 receptors, which engages the Ras/Mapk cascade with Shh, and that this niche interaction is essential for promoting GNP ciliogenesis. As GNPs leave the GZ, differentiation is driven by changing extracellular cues that diminish Siah2-activity leading to primary cilia shortening and attenuation of the mitogenic response.


Assuntos
Cílios/metabolismo , Matriz Extracelular/metabolismo , Neurônios/citologia , Proteínas Nucleares/metabolismo , Células-Tronco/citologia , Ubiquitina-Proteína Ligases/metabolismo , Animais , Diferenciação Celular , Linhagem Celular Tumoral , Cerebelo/citologia , Cerebelo/metabolismo , Cílios/genética , Matriz Extracelular/genética , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Proteínas Nucleares/genética , Transdução de Sinais , Células-Tronco/metabolismo , Ubiquitina-Proteína Ligases/genética
9.
Nat Commun ; 11(1): 5453, 2020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-33116139

RESUMO

The coronavirus SARS-CoV-2 is the causative agent of the ongoing severe acute respiratory disease pandemic COVID-19. Tissue and cellular tropism is one key to understanding the pathogenesis of SARS-CoV-2. We investigate the expression and subcellular localization of the SARS-CoV-2 receptor, angiotensin-converting enzyme 2 (ACE2), within the upper (nasal) and lower (pulmonary) respiratory tracts of human donors using a diverse panel of banked tissues. Here, we report our discovery that the ACE2 receptor protein robustly localizes within the motile cilia of airway epithelial cells, which likely represents the initial or early subcellular site of SARS-CoV-2 viral entry during host respiratory transmission. We further determine whether ciliary ACE2 expression in the upper airway is influenced by patient demographics, clinical characteristics, comorbidities, or medication use, and show the first mechanistic evidence that the use of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II receptor blockers (ARBs) does not increase susceptibility to SARS-CoV-2 infection through enhancing the expression of ciliary ACE2 receptor. These findings are crucial to our understanding of the transmission of SARS-CoV-2 for prevention and control of this virulent pathogen.


Assuntos
Antagonistas de Receptores de Angiotensina/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Infecções por Coronavirus/patologia , Expressão Gênica/efeitos dos fármacos , Peptidil Dipeptidase A/genética , Pneumonia Viral/patologia , Sistema Respiratório/patologia , Fatores Etários , Cílios/metabolismo , Infecções por Coronavirus/virologia , Células Endoteliais , Células Caliciformes/metabolismo , Humanos , Pulmão/patologia , Pandemias , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/virologia , Sistema Respiratório/metabolismo , Sistema Respiratório/virologia , Fatores Sexuais , Sinusite/metabolismo , Fumar
10.
Nat Cell Biol ; 22(9): 1091-1102, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32868900

RESUMO

Organs and cells must adapt to shear stress induced by biological fluids, but how fluid flow contributes to the execution of specific cell programs is poorly understood. Here we show that shear stress favours mitochondrial biogenesis and metabolic reprogramming to ensure energy production and cellular adaptation in kidney epithelial cells. Shear stress stimulates lipophagy, contributing to the production of fatty acids that provide mitochondrial substrates to generate ATP through ß-oxidation. This flow-induced process is dependent on the primary cilia located on the apical side of epithelial cells. The interplay between fluid flow and lipid metabolism was confirmed in vivo using a unilateral ureteral obstruction mouse model. Finally, primary cilium-dependent lipophagy and mitochondrial biogenesis are required to support energy-consuming cellular processes such as glucose reabsorption, gluconeogenesis and cytoskeletal remodelling. Our findings demonstrate how primary cilia and autophagy are involved in the translation of mechanical forces into metabolic adaptation.


Assuntos
Autofagia/fisiologia , Cílios/metabolismo , Cílios/fisiologia , Células Epiteliais/metabolismo , Células Epiteliais/fisiologia , Rim/metabolismo , Rim/fisiologia , Trifosfato de Adenosina/metabolismo , Animais , Linhagem Celular , Gluconeogênese/fisiologia , Glucose/metabolismo , Metabolismo dos Lipídeos/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Estresse Mecânico
11.
PLoS One ; 15(7): e0225351, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735563

RESUMO

Endothelial cilia are found in a variety of tissues including the cranial vasculature of zebrafish embryos. Recently, endothelial cells in the developing mouse retina were reported to also possess primary cilia that are potentially involved in vascular remodeling. Fish carrying mutations in intraflagellar transport (ift) genes have disrupted cilia and have been reported to have an increased rate of spontaneous intracranial hemorrhage (ICH), potentially due to disruption of the sonic hedgehog (shh) signaling pathway. However, it remains unknown whether the endothelial cells forming the retinal microvasculature in zebrafish also possess cilia, and whether endothelial cilia are necessary for development and maintenance of the blood-retinal barrier (BRB). In the present study, we found that the endothelial cells lining the zebrafish hyaloid vasculature possess primary cilia during development. To determine whether endothelial cilia are necessary for BRB integrity, ift57, ift88, and ift172 mutants, which lack cilia, were crossed with the double-transgenic zebrafish strain Tg(l-fabp:DBP-EGFP;flk1:mCherry). This strain expresses a vitamin D-binding protein (DBP) fused to enhanced green fluorescent protein (EGFP) as a tracer in the blood plasma, while the endothelial cells forming the vasculature are tagged by mCherry. The Ift mutant fish develop a functional BRB, indicating that endothelial cilia are not necessary for early BRB integrity. Additionally, although treatment of zebrafish larvae with Shh inhibitor cyclopamine results in BRB breakdown, the Ift mutant fish were not sensitized to cyclopamine-induced BRB breakdown.


Assuntos
Barreira Hematorretiniana/metabolismo , Cílios/metabolismo , Células Endoteliais/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Animais Geneticamente Modificados , Barreira Hematorretiniana/efeitos dos fármacos , Barreira Hematorretiniana/fisiologia , Células Endoteliais/citologia , Proteínas Hedgehog/antagonistas & inibidores , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Larva/metabolismo , Mutagênese , Vasos Retinianos/citologia , Transdução de Sinais , Alcaloides de Veratrum/farmacologia , Peixe-Zebra/crescimento & desenvolvimento , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
12.
J Vis Exp ; (161)2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32804169

RESUMO

Mucociliary epithelium provides the first line of defense by removing foreign particles through the action of mucus production and cilia-mediated clearance. Many clinically relevant defects in the mucociliary epithelium are inferred as they occur deep within the body. Here, we introduce a tractable 3D model for mucociliary epithelium generated from multipotent progenitors that were microsurgically isolated from Xenopus laevis embryos. The mucociliary epithelial organoids are covered with newly generated epithelium from deep ectoderm cells and later decorated with distinct patterned multiciliated cells, secretory cells, and mucus-producing goblet cells that are indistinguishable from the native epidermis within 24 h. The full sequences of dynamic cell transitions from mesenchymal to epithelial that emerge on the apical surface of organoids can be tracked by high-resolution live imaging. These in vitro cultured, self-organizing mucociliary epithelial organoids offer distinct advantages in studying the biology of mucociliary epithelium with high-efficiency in generation, defined culture conditions, control over number and size, and direct access for live imaging during the regeneration of the differentiated epithelium.


Assuntos
Técnicas de Cultura de Células/métodos , Cílios/metabolismo , Embrião não Mamífero/citologia , Células Epiteliais/citologia , Imageamento Tridimensional , Muco/metabolismo , Organoides/diagnóstico por imagem , Xenopus laevis/embriologia , Animais , Ectoderma/citologia , Células Epiteliais/metabolismo , Microcirurgia , Fixação de Tecidos
13.
Am J Physiol Lung Cell Mol Physiol ; 319(4): L603-L619, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32783615

RESUMO

Respiratory cilia are the driving force of the mucociliary escalator, working in conjunction with secreted airway mucus to clear inhaled debris and pathogens from the conducting airways. Respiratory cilia are also one of the first contact points between host and inhaled pathogens. Impaired ciliary function is a common pathological feature in patients with chronic airway diseases, increasing susceptibility to respiratory infections. Common respiratory pathogens, including viruses, bacteria, and fungi, have been shown to target cilia and/or ciliated airway epithelial cells, resulting in a disruption of mucociliary clearance that may facilitate host infection. Despite being an integral component of airway innate immunity, the role of respiratory cilia and their clinical significance during airway infections are still poorly understood. This review examines the expression, structure, and function of respiratory cilia during pathogenic infection of the airways. This review also discusses specific known points of interaction of bacteria, fungi, and viruses with respiratory cilia function. The emerging biological functions of motile cilia relating to intracellular signaling and their potential immunoregulatory roles during infection will also be discussed.


Assuntos
Bactérias/imunologia , Cílios/metabolismo , Fungos/imunologia , Depuração Mucociliar/fisiologia , Vírus/imunologia , Células Epiteliais/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Humanos , Imunidade Inata/imunologia , Muco/metabolismo , Sistema Respiratório/imunologia
14.
PLoS Genet ; 16(8): e1008691, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32764743

RESUMO

Primary ciliary dyskinesia (PCD) is characterized by chronic airway disease, reduced fertility, and randomization of the left/right body axis. It is caused by defects of motile cilia and sperm flagella. We screened a cohort of affected individuals that lack an obvious axonemal defect for pathogenic variants using whole exome capture, next generation sequencing, and bioinformatic analysis assuming an autosomal recessive trait. We identified one subject with an apparently homozygous nonsense variant [(c.1762C>T), p.(Arg588*)] in the uncharacterized CFAP57 gene. Interestingly, the variant results in the skipping of exon 11 (58 amino acids), which may be due to disruption of an exonic splicing enhancer. In normal human nasal epithelial cells, CFAP57 localizes throughout the ciliary axoneme. Nasal cells from the PCD patient express a shorter, mutant version of CFAP57 and the protein is not incorporated into the axoneme. The missing 58 amino acids include portions of WD repeats that may be important for loading onto the intraflagellar transport (IFT) complexes for transport or docking onto the axoneme. A reduced beat frequency and an alteration in ciliary waveform was observed. Knockdown of CFAP57 in human tracheobronchial epithelial cells (hTECs) recapitulates these findings. Phylogenetic analysis showed that CFAP57 is highly conserved in organisms that assemble motile cilia. CFAP57 is allelic with the BOP2/IDA8/FAP57 gene identified previously in Chlamydomonas reinhardtii. Two independent, insertional fap57 Chlamydomonas mutant strains show reduced swimming velocity and altered waveforms. Tandem mass tag (TMT) mass spectroscopy shows that FAP57 is missing, and the "g" inner dyneins (DHC7 and DHC3) and the "d" inner dynein (DHC2) are reduced, but the FAP57 paralog FBB7 is increased. Together, our data identify a homozygous variant in CFAP57 that causes PCD that is likely due to a defect in the inner dynein arm assembly process.


Assuntos
Axonema/metabolismo , Transtornos da Motilidade Ciliar/genética , Códon sem Sentido , Dineínas/metabolismo , Proteínas/genética , Células 3T3 , Adulto , Animais , Axonema/fisiologia , Células Cultivadas , Chlamydomonas reinhardtii , Cílios/metabolismo , Cílios/fisiologia , Transtornos da Motilidade Ciliar/patologia , Sequência Conservada , Humanos , Masculino , Camundongos , Proteínas Associadas aos Microtúbulos , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas/química , Proteínas/metabolismo , Mucosa Respiratória/metabolismo
16.
Am J Physiol Cell Physiol ; 319(2): C404-C418, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32520609

RESUMO

The ADP-ribosylation factor (ARF) superfamily of regulatory GTPases, including both the ARF and ARF-like (ARL) proteins, control a multitude of cellular functions, including aspects of vesicular traffic, lipid metabolism, mitochondrial architecture, the assembly and dynamics of the microtubule and actin cytoskeletons, and other pathways in cell biology. Considering their general utility, it is perhaps not surprising that increasingly ARF/ARLs have been found in connection to primary cilia. Here, we critically evaluate the current knowledge of the roles four ARF/ARLs (ARF4, ARL3, ARL6, ARL13B) play in cilia and highlight key missing information that would help move our understanding forward. Importantly, these GTPases are themselves regulated by guanine nucleotide exchange factors (GEFs) that activate them and by GTPase-activating proteins (GAPs) that act as both effectors and terminators of signaling. We believe that the identification of the GEFs and GAPs and better models of the actions of these GTPases and their regulators will provide a much deeper understanding and appreciation of the mechanisms that underly ciliary functions and the causes of a number of human ciliopathies.


Assuntos
Fatores de Ribosilação do ADP/genética , Cílios/genética , Ciliopatias/genética , GTP Fosfo-Hidrolases/genética , Fatores de Ribosilação do ADP/classificação , Cílios/metabolismo , Ciliopatias/patologia , Citoesqueleto/genética , GTP Fosfo-Hidrolases/classificação , Proteínas Ativadoras de GTPase/genética , Fatores de Troca do Nucleotídeo Guanina/genética , Humanos , Microtúbulos/genética , Transdução de Sinais/genética
17.
Proc Natl Acad Sci U S A ; 117(24): 13571-13579, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32482850

RESUMO

Synchronized beating of cilia on multiciliated cells (MCCs) generates a directional flow of mucus across epithelia. This motility requires a "9 + 2" microtubule (MT) configuration in axonemes and the unidirectional array of basal bodies of cilia on the MCCs. However, it is not fully understood what components are needed for central MT-pair assembly as they are not continuous with basal bodies in contrast to the nine outer MT doublets. In this study, we discovered that a homozygous knockdown mouse model for MT minus-end regulator calmodulin-regulated spectrin-associated protein 3 (CAMSAP3), Camsap3 tm1a/tm1a , exhibited multiple phenotypes, some of which are typical of primary ciliary dyskinesia (PCD), a condition caused by motile cilia defects. Anatomical examination of Camsap3 tm1a/tm1a mice revealed severe nasal airway blockage and abnormal ciliary morphologies in nasal MCCs. MCCs from different tissues exhibited defective synchronized beating and ineffective generation of directional flow likely underlying the PCD-like phenotypes. In normal mice, CAMSAP3 localized to the base of axonemes and at the basal bodies in MCCs. However, in Camsap3 tm1a/tm1a , MCCs lacked CAMSAP3 at the ciliary base. Importantly, the central MT pairs were missing in the majority of cilia, and the polarity of the basal bodies was disorganized. These phenotypes were further confirmed in MCCs of Xenopus embryos when CAMSAP3 expression was knocked down by morpholino injection. Taken together, we identified CAMSAP3 as being important for the formation of central MT pairs, proper orientation of basal bodies, and synchronized beating of motile cilia.


Assuntos
Corpos Basais/metabolismo , Cílios/metabolismo , Transtornos da Motilidade Ciliar/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Animais , Axonema/metabolismo , Polaridade Celular , Transtornos da Motilidade Ciliar/genética , Células Epiteliais/metabolismo , Humanos , Camundongos , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/genética , Microtúbulos/genética , Xenopus
18.
J Vis Exp ; (159)2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32478758

RESUMO

Primary cilia are dynamically regulated during cell cycle progression, specifically during the G0/G1 phases of the cell cycle, being resorbed prior to mitosis. Primary cilia can be visualized with highly sophisticated methods, including transmission electron microscopy, 3D imaging, or using software for the automatic detection of primary cilia. However, immunofluorescent staining of primary cilia is needed to perform these methods. This publication describes a protocol for the easy detection of primary cilia in vitro by staining acetylated alpha tubulin (axoneme) and gamma tubulin (basal body). This immunofluorescent staining protocol is relatively simple and results in high-quality images. The present protocol describes how four cell lines (C2C12, MEF, NHLF, and skin fibroblasts) expressing primary cilia were fixed, immunostained, and imaged with a fluorescent or confocal microscope.


Assuntos
Cílios/metabolismo , Imunofluorescência/métodos , Microscopia Eletrônica de Transmissão/métodos , Animais , Bovinos , Humanos
19.
PLoS Biol ; 18(6): e3000679, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32555591

RESUMO

Centriolar satellites are dynamic, membraneless granules composed of over 200 proteins. They store, modify, and traffic centrosome and primary cilium proteins, and help to regulate both the biogenesis and some functions of centrosomes and cilium. In most cell types, satellites cluster around the perinuclear centrosome, but their integrity and cellular distribution are dynamically remodeled in response to different stimuli, such as cell cycle cues. Dissecting the specific and temporal functions and mechanisms of satellites and how these are influenced by their cellular positioning and dynamics has been challenging using genetic approaches, particularly in ciliated and proliferating cells. To address this, we developed a chemical-based trafficking assay to rapidly and efficiently redistribute satellites to either the cell periphery or center, and fuse them into stable clusters in a temporally controlled way. Induced satellite clustering at either the periphery or center resulted in antagonistic changes in the pericentrosomal levels of a subset of proteins, revealing a direct and selective role for their positioning in protein targeting and sequestration. Systematic analysis of the interactome of peripheral satellite clusters revealed enrichment of proteins implicated in cilium biogenesis and mitosis. Importantly, induction of peripheral satellite targeting in ciliated cells revealed a function for satellites not just for efficient cilium assembly but also in the maintenance of steady-state cilia and in cilia disassembly by regulating the structural integrity of the ciliary axoneme. Finally, perturbing satellite distribution and dynamics inhibited their mitotic dissolution, and mitotic progression was perturbed only in cells with centrosomal satellite clustering. Collectively, our results for the first time showed a direct link between satellite functions and their pericentrosomal clustering, suggested new mechanisms underlying satellite functions during cilium assembly, and provided a new tool for probing temporal satellite functions in different contexts.


Assuntos
Centríolos/metabolismo , Cílios/metabolismo , Grânulos Citoplasmáticos/metabolismo , Autoantígenos/química , Autoantígenos/metabolismo , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Células HEK293 , Células HeLa , Humanos , Mitose , Fenótipo , Domínios Proteicos , Multimerização Proteica , Reprodutibilidade dos Testes
20.
Nat Commun ; 11(1): 2188, 2020 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-32366818

RESUMO

Olfactory receptor neurons (ORNs) use odour-induced intracellular cAMP surge to gate cyclic nucleotide-gated nonselective cation (CNG) channels in cilia. Prolonged exposure to cAMP causes calmodulin-dependent feedback-adaptation of CNG channels and attenuates neural responses. On the other hand, the odour-source searching behaviour requires ORNs to be sensitive to odours when approaching targets. How ORNs accommodate these conflicting aspects of cAMP responses remains unknown. Here, we discover that olfactory marker protein (OMP) is a major cAMP buffer that maintains the sensitivity of ORNs. Upon the application of sensory stimuli, OMP directly captured and swiftly reduced freely available cAMP, which transiently uncoupled downstream CNG channel activity and prevented persistent depolarization. Under repetitive stimulation, OMP-/- ORNs were immediately silenced after burst firing due to sustained depolarization and inactivated firing machinery. Consequently, OMP-/- mice showed serious impairment in odour-source searching tasks. Therefore, cAMP buffering by OMP maintains the resilient firing of ORNs.


Assuntos
AMP Cíclico/metabolismo , Canais de Cátion Regulados por Nucleotídeos Cíclicos/metabolismo , Proteína de Marcador Olfatório/metabolismo , Neurônios Receptores Olfatórios/metabolismo , Animais , Butorfanol/farmacologia , Cílios/metabolismo , Células HEK293 , Humanos , Masculino , Medetomidina/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Midazolam/farmacologia , Odorantes , Proteína de Marcador Olfatório/genética , Mucosa Olfatória/citologia , Mucosa Olfatória/efeitos dos fármacos , Mucosa Olfatória/fisiologia , Neurônios Receptores Olfatórios/citologia , Neurônios Receptores Olfatórios/fisiologia , Técnicas de Patch-Clamp
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