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Current Opinion in Cell Biology Feb 2013Centrioles are the key foundation of centrosomes and cilia, yet a molecular understanding of how they form has only recently begun to emerge. Building a fully functional... (Review)
Review
Centrioles are the key foundation of centrosomes and cilia, yet a molecular understanding of how they form has only recently begun to emerge. Building a fully functional centriole that can form a centrosome and cilium requires two cell cycles. Centriole building starts with procentriole nucleation, a process that is coordinated by the conserved proteins Plk4/Zyg-1, and Asterless/Cep152. Subsequently, Sas-6, a conserved procentriole protein, self-assembles to provide nine-fold symmetry to the centriole scaffold. The procentriole then continues to elongate into a centriole, a process controlled by Sas-4/CPAP and CP110. Then, centrioles recruit Sas-4-mediated pre-assembled centrosomal complexes from the cytoplasm to form the pericentriolar material (PCM). Finally, CP110 and its interacting proteins are involved in controlling the timing of centriole templating of the cilium.
Topics: Animals; Cell Cycle; Centrioles; Cilia; Humans
PubMed: 23199753
DOI: 10.1016/j.ceb.2012.10.016 -
The Journal of Cell Biology Dec 2023Centriole duplication is a high-fidelity process driven by Polo-like kinase 4 (Plk4) and a few conserved initiators. Dissecting how Plk4 and its receptors organize...
Centriole duplication is a high-fidelity process driven by Polo-like kinase 4 (Plk4) and a few conserved initiators. Dissecting how Plk4 and its receptors organize within centrosomes is critical to understand the centriole duplication process and biochemical and architectural differences between centrosomes of different species. Here, at nanoscale resolution, we dissect centrosomal localization of Plk4 in G1 and S phase in its catalytically active and inhibited state during centriole duplication and amplification. We build a precise distribution map of Plk4 and its receptor Cep152, as well as Cep44, Cep192, and Cep152-anchoring factors Cep57 and Cep63. We find that Cep57, Cep63, Cep44, and Cep192 localize in ninefold symmetry. However, during centriole maturation, Cep152, which we suggest is the major Plk4 receptor, develops a more complex pattern. We propose that the molecular arrangement of Cep152 creates flexibility for Plk4 and procentriole placement during centriole initiation. As a result, procentrioles form at variable positions in relation to the mother centriole microtubule triplets.
Topics: Cell Cycle; Centrioles; Centrosome; Microtubules; S Phase; Humans; Cell Cycle Proteins; Protein Serine-Threonine Kinases
PubMed: 37707473
DOI: 10.1083/jcb.202301092 -
PLoS Biology Sep 2022Uncovering organizing principles of organelle assembly is a fundamental pursuit in the life sciences. Caenorhabditis elegans was key in identifying evolutionary...
Uncovering organizing principles of organelle assembly is a fundamental pursuit in the life sciences. Caenorhabditis elegans was key in identifying evolutionary conserved components governing assembly of the centriole organelle. However, localizing these components with high precision has been hampered by the minute size of the worm centriole, thus impeding understanding of underlying assembly mechanisms. Here, we used Ultrastructure Expansion coupled with STimulated Emission Depletion (U-Ex-STED) microscopy, as well as electron microscopy (EM) and electron tomography (ET), to decipher the molecular architecture of the worm centriole. Achieving an effective lateral resolution of approximately 14 nm, we localize centriolar and PeriCentriolar Material (PCM) components in a comprehensive manner with utmost spatial precision. We found that all 12 components analysed exhibit a ring-like distribution with distinct diameters and often with a 9-fold radial symmetry. Moreover, we uncovered that the procentriole assembles at a location on the centriole margin where SPD-2 and ZYG-1 also accumulate. Moreover, SAS-6 and SAS-5 were found to be present in the nascent procentriole, with SAS-4 and microtubules recruited thereafter. We registered U-Ex-STED and EM data using the radial array of microtubules, thus allowing us to map each centriolar and PCM protein to a specific ultrastructural compartment. Importantly, we discovered that SAS-6 and SAS-4 exhibit a radial symmetry that is offset relative to microtubules, leading to a chiral centriole ensemble. Furthermore, we established that the centriole is surrounded by a region from which ribosomes are excluded and to which SAS-7 localizes. Overall, our work uncovers the molecular architecture of the C. elegans centriole in unprecedented detail and establishes a comprehensive framework for understanding mechanisms of organelle biogenesis and function.
Topics: Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cell Cycle Proteins; Centrioles; Centrosome; Protein Kinases
PubMed: 36107993
DOI: 10.1371/journal.pbio.3001784 -
ELife Feb 2019Centriole is an essential structure with multiple functions in cellular processes. Centriole biogenesis and homeostasis is tightly regulated. Using electron...
Centriole is an essential structure with multiple functions in cellular processes. Centriole biogenesis and homeostasis is tightly regulated. Using electron cryo-tomography (cryoET) we present the structure of procentrioles from . We identified a set of non-tubulin components attached to the triplet microtubule (MT), many are at the junctions of tubules likely to reinforce the triplet. We describe structure of the A-C linker that bridges neighboring triplets. The structure infers that POC1 is likely an integral component of A-C linker. Its conserved WD40 β-propeller domain provides attachment sites for other A-C linker components. The twist of A-C linker results in an iris diaphragm-like motion of the triplets in the longitudinal direction of procentriole. Finally, we identified two assembly intermediates at the growing ends of procentriole allowing us to propose a model for the procentriole assembly. Our results provide a comprehensive structural framework for understanding the molecular mechanisms underpinning procentriole biogenesis and assembly.
Topics: Cell Cycle; Cell Cycle Proteins; Centrioles; Chlamydomonas reinhardtii; Cryoelectron Microscopy; Electron Microscope Tomography; Microtubules
PubMed: 30741631
DOI: 10.7554/eLife.43434 -
The Journal of Cell Biology Feb 2020During centriole duplication, a preprocentriole forms at a single site on the mother centriole through a process that includes the hierarchical recruitment of a...
During centriole duplication, a preprocentriole forms at a single site on the mother centriole through a process that includes the hierarchical recruitment of a conserved set of proteins, including the Polo-like kinase 4 (Plk4), Ana2/STIL, and the cartwheel protein Sas6. Ana2/STIL is critical for procentriole assembly, and its recruitment is controlled by the kinase activity of Plk4, but how this works remains poorly understood. A structural motif called the G-box in the centriole outer wall protein Sas4 interacts with a short region in the N terminus of Ana2/STIL. Here, we show that binding of Ana2 to the Sas4 G-box enables hyperphosphorylation of the Ana2 N terminus by Plk4. Hyperphosphorylation increases the affinity of the Ana2-G-box interaction, and, consequently, promotes the accumulation of Ana2 at the procentriole to induce daughter centriole formation.
Topics: Animals; Cell Cycle; Cell Cycle Proteins; Cell Line; Centrioles; Drosophila Proteins; Drosophila melanogaster; Intracellular Signaling Peptides and Proteins; Microtubule-Associated Proteins; Phosphorylation; Protein Binding; Protein Serine-Threonine Kinases
PubMed: 31841145
DOI: 10.1083/jcb.201905172 -
The Journal of Cell Biology Dec 2023Polo-like kinase 4 (PLK4) is a key regulator of centriole biogenesis, but how PLK4 selects a single site for procentriole assembly remains unclear. Using ultrastructure...
Polo-like kinase 4 (PLK4) is a key regulator of centriole biogenesis, but how PLK4 selects a single site for procentriole assembly remains unclear. Using ultrastructure expansion microscopy, we show that PLK4 localizes to discrete sites along the wall of parent centrioles. While there is variation in the number of sites PLK4 occupies on the parent centriole, most PLK4 localize at a dominant site that directs procentriole assembly. Inhibition of PLK4 activity leads to stable binding of PLK4 to the centriole and increases occupancy to a maximum of nine sites. We show that self-phosphorylation of an unstructured linker promotes the release of active PLK4 from the centriole to drive the selection of a single site for procentriole assembly. Preventing linker phosphorylation blocks PLK4 turnover, leading to supernumerary sites of PLK4 localization and centriole amplification. Therefore, self-phosphorylation is a major driver of the spatial patterning of PLK4 at the centriole and plays a critical role in selecting a single centriole duplication site.
Topics: Cell Cycle; Cell Cycle Proteins; Centrioles; Phosphorylation; Humans; Protein Serine-Threonine Kinases
PubMed: 37773039
DOI: 10.1083/jcb.202301069 -
Communications Biology Jul 2023Proper organization of intracellular assemblies is fundamental for efficient promotion of biochemical processes and optimal assembly functionality. Although advances in...
Proper organization of intracellular assemblies is fundamental for efficient promotion of biochemical processes and optimal assembly functionality. Although advances in imaging technologies have shed light on how the centrosome is organized, how its constituent proteins are coherently architected to elicit downstream events remains poorly understood. Using multidisciplinary approaches, we showed that two long coiled-coil proteins, Cep63 and Cep152, form a heterotetrameric building block that undergoes a stepwise formation into higher molecular weight complexes, ultimately generating a cylindrical architecture around a centriole. Mutants defective in Cep63•Cep152 heterotetramer formation displayed crippled pericentriolar Cep152 organization, polo-like kinase 4 (Plk4) relocalization to the procentriole assembly site, and Plk4-mediated centriole duplication. Given that the organization of pericentriolar materials (PCM) is evolutionarily conserved, this work could serve as a model for investigating the structure and function of PCM in other species, while offering a new direction in probing the organizational defects of PCM-related human diseases.
Topics: Humans; Cell Cycle; Centrioles; Centrosome; Molecular Weight; Protein Domains; Protein Serine-Threonine Kinases
PubMed: 37433832
DOI: 10.1038/s42003-023-05067-8 -
The EMBO Journal Oct 2011Centriole duplication involves the growth of a procentriole next to the parental centriole. Mutations in STIL and CPAP/CENPJ cause primary microcephaly (MCPH). Here, we...
Centriole duplication involves the growth of a procentriole next to the parental centriole. Mutations in STIL and CPAP/CENPJ cause primary microcephaly (MCPH). Here, we show that human STIL has an asymmetric localization to the daughter centriole and is required for procentriole formation. STIL levels oscillate during the cell cycle. Interestingly, STIL interacts directly with CPAP and forms a complex with hSAS6. A natural mutation of CPAP (E1235V) that causes MCPH in humans leads to significantly lower binding to STIL. Overexpression of STIL induced the formation of multiple procentrioles around the parental centriole. STIL depletion inhibited normal centriole duplication, Plk4-induced centriole amplification, and CPAP-induced centriole elongation, and resulted in a failure to localize hSAS6 and CPAP to the base of the nascent procentriole. Furthermore, hSAS6 depletion hindered STIL targeting to the procentriole, implying that STIL and hSAS6 are mutually dependent for their centriolar localization. Together, our results indicate that the two MCPH-associated proteins STIL and CPAP interact with each other and are required for procentriole formation, implying a central role of centriole biogenesis in MCPH.
Topics: Animals; Cattle; Cell Cycle; Cell Cycle Proteins; Cell Division; Cells, Cultured; Centrioles; HEK293 Cells; HeLa Cells; Humans; Intracellular Signaling Peptides and Proteins; Microcephaly; Microscopy, Confocal; Microscopy, Fluorescence; Microtubule-Associated Proteins; Protein Binding
PubMed: 22020124
DOI: 10.1038/emboj.2011.378 -
Molecular Biology of the Cell Jul 2017The decision to commit to the cell cycle is made during G1 through the concerted action of various cyclin-CDK complexes. Not only DNA replication, but also centriole...
The decision to commit to the cell cycle is made during G1 through the concerted action of various cyclin-CDK complexes. Not only DNA replication, but also centriole duplication is initiated as cells enter the S-phase. The NIMA-related kinase NEK7 is one of many factors required for proper centriole duplication, as well as for timely cell cycle progression. However, its specific roles in these events are poorly understood. In this study, we find that depletion of NEK7 inhibits progression through the G1 phase in human U2OS cells via down-regulation of various cyclins and CDKs and also inhibits the earliest stages of procentriole formation. Depletion of NEK7 also induces formation of primary cilia in human RPE1 cells, suggesting that NEK7 acts at least before the restriction point during G1. G1-arrested cells in the absence of NEK7 exhibit abnormal accumulation of the APC/C cofactor Cdh1 at the vicinity of centrioles. Furthermore, the ubiquitin ligase APC/C continuously degrades the centriolar protein STIL in these cells, thus inhibiting centriole assembly. Collectively our results demonstrate that NEK7 is involved in the timely regulation of G1 progression, S-phase entry, and procentriole formation.
Topics: Cell Cycle Proteins; Cell Division; Cells, Cultured; Centrioles; Cilia; Cyclin-Dependent Kinases; Cyclins; DNA Replication; G1 Phase; G1 Phase Cell Cycle Checkpoints; Humans; NIMA-Related Kinases; Phosphorylation; S Phase
PubMed: 28539406
DOI: 10.1091/mbc.E16-09-0643 -
Cells Jun 2020Centrioles are microtubule-based cellular structures present in most human cells that build centrosomes and cilia. Proliferating cells have only two centrosomes and this... (Review)
Review
Centrioles are microtubule-based cellular structures present in most human cells that build centrosomes and cilia. Proliferating cells have only two centrosomes and this number is stringently maintained through the temporally and spatially controlled processes of centriole assembly and segregation. The assembly of new centrioles begins in early S phase and ends in the third G1 phase from their initiation. This lengthy process of centriole assembly from their initiation to their maturation is characterized by numerous structural and still poorly understood biochemical changes, which occur in synchrony with the progression of cells through three consecutive cell cycles. As a result, proliferating cells contain three structurally, biochemically, and functionally distinct types of centrioles: procentrioles, daughter centrioles, and mother centrioles. This age difference is critical for proper centrosome and cilia function. Here we discuss the centriole assembly process as it occurs in somatic cycling human cells with a focus on the structural, biochemical, and functional characteristics of centrioles of different ages.
Topics: Aging; Centrioles; Centrosome; Humans
PubMed: 32526902
DOI: 10.3390/cells9061429