-
Molecular Biology of the Cell Jul 2022The centriole is a minute cylindrical organelle present in a wide range of eukaryotic species. Most centrioles have a signature ninefold radial symmetry of microtubules...
The centriole is a minute cylindrical organelle present in a wide range of eukaryotic species. Most centrioles have a signature ninefold radial symmetry of microtubules that is imparted to the axonemes of the cilia and flagella they template, with nine centriolar microtubule doublets growing into nine axonemal microtubule doublets. There are exceptions to the ninefold symmetrical arrangement of axonemal microtubules in some species, with lower or higher fold symmetries. In the few cases where this has been examined, such alterations in axonemal symmetries are grounded in similar alterations in centriolar symmetries. Here, we examine the question of microtubule number continuity between centriole and axoneme in flagellated gametes of the gregarine , which have been reported to exhibit a sixfold radial symmetry of axonemal microtubules. We used time-lapse differential interference microscopy to identify the stage at which flagellated gametes are present. Thereafter, using electron microscopy and ultrastructure-expansion microscopy coupled to stimulated emission depletion superresolution imaging, we uncover that a six- or fivefold radial symmetry in the axoneme is accompanied by an eightfold radial symmetry in the centriole. We conclude that the transition between centriolar and axonemal microtubules can be characterized by unexpected plasticity.
Topics: Apicomplexa; Axoneme; Centrioles; Cilia; Flagella; Microtubules
PubMed: 35544302
DOI: 10.1091/mbc.E22-04-0123 -
Current Biology : CB Aug 2023The molecular mechanism underlying asymmetric axonemal complexes in sperm flagella is still largely unknown. Here, we showed that the knockout of the coiled-coil...
The molecular mechanism underlying asymmetric axonemal complexes in sperm flagella is still largely unknown. Here, we showed that the knockout of the coiled-coil domain-containing 176 (CCDC176) in mice led to male infertility due to decreased sperm motility. Ccdc176 knockout specifically destabilized microtubule doublets (MTDs) 1 and 9 during sperm maturation in the corpus epididymis. Single-sperm immunofluorescence showed that most CCDC176 was distributed along the axoneme, and further super-resolution imaging revealed that CCDC176 is asymmetrically localized in the sperm axoneme. CCDC176 could cooperate with microtubule and radial spoke proteins to stabilize MTDs 1 and 9, and its knockout results in the destabilization of some proteins in sperm flagella. Furthermore, as predicted by the sperm multibody dynamics (MBD) model, we found that MTDs 1 and 9 jutted out from the sperm flagellum annulus region in Ccdc176 spermatozoa, and these flagellar defects alter sperm flagellar beat patterns and swimming paths, potentially owing to the reduction and disequilibration of bending torque on the central pair. These results demonstrate that CCDC176 specifically stabilizes MTDs 1 and 9 in the sperm flagellum to ensure proper sperm movement for fertilization.
Topics: Male; Animals; Mice; Sperm Motility; Semen; Sperm Tail; Spermatozoa; Flagella; Microtubules; Axoneme
PubMed: 37494937
DOI: 10.1016/j.cub.2023.06.079 -
Nature Communications Nov 2020Axonemal dynein ATPases direct ciliary and flagellar beating via adenosine triphosphate (ATP) hydrolysis. The modulatory effect of adenosine monophosphate (AMP) and...
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.
Topics: Adenine Nucleotides; Adolescent; Adult; Animals; Asthenozoospermia; Axoneme; CRISPR-Cas Systems; Cilia; Cytoskeletal Proteins; DNA Mutational Analysis; Disease Models, Animal; Epididymis; Female; Flagella; Humans; Loss of Function Mutation; Male; Mice; Mice, Knockout; Middle Aged; Planarians; Respiratory Mucosa; Situs Inversus; Sperm Motility; Tomography, X-Ray Computed; Exome Sequencing
PubMed: 33139725
DOI: 10.1038/s41467-020-19113-0 -
Mammalian axoneme central pair complex proteins: Broader roles revealed by gene knockout phenotypes.Cytoskeleton (Hoboken, N.J.) Jan 2016The axoneme genes, their encoded proteins, their functions and the structures they form are largely conserved across species. Much of our knowledge of the function and... (Review)
Review
The axoneme genes, their encoded proteins, their functions and the structures they form are largely conserved across species. Much of our knowledge of the function and structure of axoneme proteins in cilia and flagella is derived from studies on model organisms like the green algae, Chlamydomonas reinhardtii. The core structure of cilia and flagella is the axoneme, which in most motile cilia and flagella contains a 9 + 2 configuration of microtubules. The two central microtubules are the scaffold of the central pair complex (CPC). Mutations that disrupt CPC genes in Chlamydomonas and other model organisms result in defects in assembly, stability and function of the axoneme, leading to flagellar motility defects. However, targeted mutations generated in mice in the orthologous CPC genes have revealed significant differences in phenotypes of mutants compared to Chlamydomonas. Here we review observations that support the concept of cell-type specific roles for the CPC genes in mice, and an expanded repertoire of functions for the products of these genes in cilia, including non-motile cilia, and other microtubule-associated cellular functions.
Topics: Animals; Axoneme; Cytoskeletal Proteins; Gene Knockout Techniques; Humans; Mice; Microtubule Proteins; Microtubule-Associated Proteins
PubMed: 26785425
DOI: 10.1002/cm.21271 -
European Respiratory Review : An... Dec 2023Cilia are organelles emanating from the cell surface, consisting of an axoneme of microtubules that extends from a basal body derived from the centrioles. They are... (Review)
Review
Cilia are organelles emanating from the cell surface, consisting of an axoneme of microtubules that extends from a basal body derived from the centrioles. They are either isolated and nonmotile (primary cilia), or grouped and motile (motile cilia). Cilia are at the centre of fundamental sensory processes and are involved in a wide range of human disorders. Pulmonary cilia include motile cilia lining the epithelial cells of the conductive airways to orchestrate mucociliary clearance, and primary cilia found on nondifferentiated epithelial and mesenchymal cells acting as sensors and cell cycle keepers. Whereas cilia are essential along the airways, their regulatory molecular mechanisms remain poorly understood, resulting in a lack of therapeutic strategies targeting their structure or functions. This review summarises the current knowledge on cilia in the context of lung homeostasis and COPD to provide a comprehensive overview of the (patho)biology of cilia in respiratory medicine with a particular emphasis on COPD.
Topics: Humans; Lung; Mucociliary Clearance; Axoneme; Cilia; Epithelial Cells; Homeostasis; Pulmonary Disease, Chronic Obstructive
PubMed: 38056888
DOI: 10.1183/16000617.0106-2023 -
Cold Spring Harbor Perspectives in... Aug 2017Ciliary motility is crucial for the development and health of many organisms. Motility depends on the coordinated activity of multiple dynein motors arranged in a... (Review)
Review
Ciliary motility is crucial for the development and health of many organisms. Motility depends on the coordinated activity of multiple dynein motors arranged in a precise pattern on the outer doublet microtubules. Although significant progress has been made in elucidating the composition and organization of the dyneins, a comprehensive understanding of dynein regulation is lacking. Here, we focus on two conserved signaling complexes located at the base of the radial spokes. These include the I1/ inner dynein arm associated with radial spoke 1 and the calmodulin- and spoke-associated complex and the nexin-dynein regulatory complex associated with radial spoke 2. Current research is focused on understanding how these two axonemal hubs coordinate and regulate the dynein motors and ciliary motility.
Topics: Animals; Axoneme; Cilia; Dyneins; Humans; Movement
PubMed: 28765157
DOI: 10.1101/cshperspect.a018325 -
Nature Communications Jan 2024Tubulin-based microtubule is a core component of flagella axoneme and essential for sperm motility and male fertility. Structural components of the axoneme have been...
Tubulin-based microtubule is a core component of flagella axoneme and essential for sperm motility and male fertility. Structural components of the axoneme have been well explored. However, how tubulin folding is regulated in sperm flagella formation is still largely unknown. Here, we report a germ cell-specific co-factor of CCT complex, STYXL1. Deletion of Styxl1 results in male infertility and microtubule defects of sperm flagella. Proteomic analysis of Styxl1 sperm reveals abnormal downregulation of flagella-related proteins including tubulins. The N-terminal rhodanese-like domain of STYXL1 is important for its interactions with CCT complex subunits, CCT1, CCT6 and CCT7. Styxl1 deletion leads to defects in CCT complex assembly and tubulin polymerization. Collectively, our findings reveal the vital roles of germ cell-specific STYXL1 in CCT-facilitated tubulin folding and sperm flagella development.
Topics: Male; Humans; Tubulin; Proteomics; Sperm Motility; Semen; Spermatozoa; Flagella; Axoneme
PubMed: 38168070
DOI: 10.1038/s41467-023-44337-1 -
Cellular and Molecular Life Sciences :... May 2023The sperm flagellum is a specialized type of motile cilium composed of a typical "9 + 2" axonemal structure with peri-axonemal structures, such as outer dense fibers...
The sperm flagellum is a specialized type of motile cilium composed of a typical "9 + 2" axonemal structure with peri-axonemal structures, such as outer dense fibers (ODFs). This flagellar arrangement is crucial for sperm movement and fertilization. However, the association of axonemal integrity with ODFs remains poorly understood. Here, we demonstrate that mouse BBOF1 could interact with both MNS1, an axonemal component, and ODF2, an ODF protein, and is required for sperm flagellar axoneme maintenance and male fertility. BBOF1 is expressed exclusively in male germ cells from the pachytene stage onwards and is detected in sperm axoneme fraction. Spermatozoa derived from Bbof1-knockout mice exhibit a normal morphology, however, reduced motility due to the absence of certain microtubule doublets, resulting in the failure to fertilize mature oocytes. Furthermore, BBOF1 is found to interact with ODF2 and MNS1 and is also required for their stability. Our findings in mice suggest that Bbof1 could also be essential for human sperm motility and male fertility, thus is a novel potential candidate gene for asthenozoospermia diagnosis.
Topics: Animals; Male; Mice; Axoneme; Fertility; Heat-Shock Proteins; Infertility, Male; Mice, Knockout; Semen; Sperm Motility; Spermatozoa
PubMed: 37198331
DOI: 10.1007/s00018-023-04800-0 -
The Journal of Cell Biology Sep 2018Primary cilia are polarized organelles that allow detection of extracellular signals such as Hedgehog (Hh). How the cytoskeleton supporting the cilium generates and...
Primary cilia are polarized organelles that allow detection of extracellular signals such as Hedgehog (Hh). How the cytoskeleton supporting the cilium generates and maintains a structure that finely tunes cellular response remains unclear. Here, we find that regulation of actin polymerization controls primary cilia and Hh signaling. Disrupting actin polymerization, or knockdown of N-WASp/Arp3, increases ciliation frequency, axoneme length, and Hh signaling. Cdc42, a potent actin regulator, recruits both atypical protein pinase C iota/lambda (aPKC) and Missing-in-Metastasis (MIM) to the basal body to maintain actin polymerization and restrict axoneme length. Transcriptome analysis implicates the Src pathway as a major aPKC effector. aPKC promotes whereas MIM antagonizes Src activity to maintain proper levels of primary cilia, actin polymerization, and Hh signaling. Hh pathway activation requires Smoothened-, Gli-, and Gli1-specific activation by aPKC. Surprisingly, longer axonemes can amplify Hh signaling, except when aPKC is disrupted, reinforcing the importance of the Cdc42-aPKC-Gli axis in actin-dependent regulation of primary cilia signaling.
Topics: 3T3 Cells; Actin-Related Protein 3; Actins; Animals; Axoneme; Basal Bodies; Cell Line; Cilia; Enzyme Activation; Gene Expression Regulation; Hedgehog Proteins; Mice; Microfilament Proteins; Neoplasm Proteins; Polymerization; Protein Kinase C; Signal Transduction; Wiskott-Aldrich Syndrome Protein, Neuronal; Zinc Finger Protein GLI1; cdc42 GTP-Binding Protein; src-Family Kinases
PubMed: 29945904
DOI: 10.1083/jcb.201703196 -
Journal of Cell Science Aug 2021Axonemal dyneins power the beating of motile cilia and flagella. These massive multimeric motor complexes are assembled in the cytoplasm, and subsequently trafficked to...
Axonemal dyneins power the beating of motile cilia and flagella. These massive multimeric motor complexes are assembled in the cytoplasm, and subsequently trafficked to cilia and incorporated into the axonemal superstructure. Numerous cytoplasmic factors are required for the dynein assembly process, and, in mammals, defects lead to primary ciliary dyskinesia, which results in infertility, bronchial problems and failure to set up the left-right body axis correctly. Liquid-liquid phase separation (LLPS) has been proposed to underlie the formation of numerous membrane-less intracellular assemblies or condensates. In multiciliated cells, cytoplasmic assembly of axonemal dyneins also occurs in condensates that exhibit liquid-like properties, including fusion, fission and rapid exchange of components both within condensates and with bulk cytoplasm. However, a recent extensive meta-analysis suggests that the general methods used to define LLPS systems in vivo may not readily distinguish LLPS from other mechanisms. Here, I consider the time and length scales of axonemal dynein heavy chain synthesis, and the possibility that during translation of dynein heavy chain mRNAs, polysomes are crosslinked via partially assembled proteins. I propose that axonemal dynein factory formation in the cytoplasm may be a direct consequence of the sheer scale and complexity of the assembly process itself.
Topics: Animals; Axonemal Dyneins; Axoneme; Cilia; Cytoplasm; Dyneins; Flagella
PubMed: 34342348
DOI: 10.1242/jcs.258626