Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Building a ninefold symmetrical barrel: structural dissections of centriole assembly.

ABSTRACT: Centrioles are short microtubule-based organelles with a conserved ninefold symmetry. They are essential for both centrosome formation and cilium biogenesis in most eukaryotes. A core set of five centriolar proteins has been identified and their sequential recruitment to procentrioles has been established. However, structures at atomic resolution for most of the centriolar components were scarce, and the underlying molecular mechanisms for centriole assembly had been a mystery--until recently. In this review, I briefly summarize recent advancements in high-resolution structural characterization of the core centriolar components and discuss perspectives in the field.

SUBMITTER: Dong G

PROVIDER: S-EPMC4554922 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Building a ninefold symmetrical barrel: structural dissections of centriole assembly.

Dong Gang G

Open biology 20150801 8

Centrioles are short microtubule-based organelles with a conserved ninefold symmetry. They are essential for both centrosome formation and cilium biogenesis in most eukaryotes. A core set of five centriolar proteins has been identified and their sequential recruitment to procentrioles has been established. However, structures at atomic resolution for most of the centriolar components were scarce, and the underlying molecular mechanisms for centriole assembly had been a mystery--until recently. I ...[more]

PMID: 26269428

Similar Datasets

Bld10p, a novel protein essential for basal body assembly in Chlamydomonas: localization to the cartwheel, the first ninefold symmetrical structure appearing during assembly.

Project description:How centrioles and basal bodies assemble is a long-standing puzzle in cell biology. To address this problem, we analyzed a novel basal body-defective Chlamydomonas reinhardtii mutant isolated from a collection of flagella-less mutants. This mutant, bld10, displayed disorganized mitotic spindles and cytoplasmic microtubules, resulting in abnormal cell division and slow growth. Electron microscopic observation suggested that bld10 cells totally lack basal bodies. The product of the BLD10 gene (Bld10p) was found to be a novel coiled-coil protein of 170 kD. Immunoelectron microscopy localizes Bld10p to the cartwheel, a structure with ninefold rotational symmetry positioned near the proximal end of the basal bodies. Because the cartwheel forms the base from which the triplet microtubules elongate, we suggest that Bld10p plays an essential role in an early stage of basal body assembly. A viable mutant having such a severe basal body defect emphasizes the usefulness of Chlamydomonas in studying the mechanism of basal body/centriole assembly by using a variety of mutants.

| S-EPMC2172387 | biostudies-literature

Structural snapshots of the β-barrel assembly machinery.

Project description:The β-barrel assembly machinery (BAM) is a multicomponent complex responsible for the biogenesis of β-barrel outer membrane proteins (OMPs) in Gram-negative bacteria, with conserved systems in both mitochondria and chloroplasts. Given its importance in the integrity of the outer membrane and in the assembly of surface exposed virulence factors, BAM is an attractive therapeutic target against pathogenic bacteria, particularly multidrug-resistant strains. While the mechanism for how BAM functions remains elusive, previous structural studies have described each of the individual components of BAM, offering only a few clues to how the complex functions. Recently, a number of structures have been reported of complexes, including that of fully assembled BAM in differing conformational states. These studies have provided the molecular blueprint detailing the atomic interactions between the components and have revealed new details about BAM, which suggest a dynamic mechanism that may use conformational changes to assist in the biogenesis of new OMPs.

| S-EPMC5429997 | biostudies-literature

Structural basis for assembly of vertical single ?-barrel viruses.

Project description:The vertical double ?-barrel major capsid protein (MCP) fold, fingerprint of the PRD1-adeno viral lineage, is widespread in many viruses infecting organisms across the three domains of life. The discovery of PRD1-like viruses with two MCPs challenged the known assembly principles. Here, we present the cryo-electron microscopy (cryo-EM) structures of the archaeal, halophilic, internal membrane-containing Haloarcula californiae icosahedral virus 1 (HCIV-1) and Haloarcula hispanica icosahedral virus 2 (HHIV-2) at 3.7 and 3.8?Å resolution, respectively. Our structures reveal proteins located beneath the morphologically distinct two- and three-tower capsomers and homopentameric membrane proteins at the vertices that orchestrate the positioning of pre-formed vertical single ?-barrel MCP heterodimers. The cryo-EM based structures together with the proteomics data provide insights into the assembly mechanism of this type of viruses and into those with membrane-less double ?-barrel MCPs.

| S-EPMC6414509 | biostudies-literature

Structural basis for substrate selection by the translocation and assembly module of the ?-barrel assembly machinery.

Project description:The assembly of proteins into bacterial outer membranes is a key cellular process that we are only beginning to understand, mediated by the ?-barrel assembly machinery (BAM). Two crucial elements of that machinery are the core BAM complex and the translocation and assembly module (TAM), with each containing a member of the Omp85 superfamily of proteins: BamA in the BAM complex, TamA in the TAM. Here, we used the substrate protein FimD as a model to assess the selectivity of substrate interactions for the TAM relative to those of the BAM complex. A peptide scan revealed that TamA and BamA bind the ?-strands of FimD, and do so selectively. Chemical cross-linking and molecular dynamics are consistent with this interaction taking place between the first and last strand of the TamA barrel domain, providing the first experimental evidence of a lateral gate in TamA: a structural element implicated in membrane protein assembly. We suggest that the lateral gates in TamA and BamA provide different environments for substrates to engage, with the differences observed here beginning to address how the TAM can be more effective than the BAM complex in the folding of some substrate proteins.

| S-EPMC5607099 | biostudies-literature

TtOmp85, a β-barrel assembly protein, functions by barrel augmentation.

Project description:Outer membrane proteins are vital for Gram-negative bacteria and organisms that inherited organelles from them. Proteins from the Omp85/BamA family conduct the insertion of membrane proteins into the outer membrane. We show that an eight-stranded outer membrane β-barrel protein, TtoA, is inserted and folded into liposomes by an Omp85 homologue. Furthermore, we recorded the channel conductance of this Omp85 protein in black lipid membranes, alone and in the presence of peptides comprising the sequence of the two N-terminal and the two C-terminal β-strands of TtoA. Only with the latter could a long-living compound channel that exhibits conductance levels higher than those of the Omp85 protein alone be observed. These data support a model in which unfolded outer membrane protein after docking with its C-terminus penetrates into the transmembrane β-barrel of the Omp85 protein and augments its β-sheet at the first strand. Augmentation with successive β-strands leads to a compound, dilated barrel of both proteins.

| S-EPMC4310625 | biostudies-literature

Multicilin promotes centriole assembly and ciliogenesis during multiciliate cell differentiation.

Project description:Analysis of epithelial explants injected with the intracellular domain of Notch (ICD) alone, to block the formation of multiciliate cells, or with Dexamethasone inducible Multicilin (MCI-HGR) to induce the formation of ectopic multiciliate cells. MCI-HGR plus ICD injected samples were compared to ICD alone to identify candidate genes whose expression changes when MCI is active. Epithelial cells projecting hundreds of motile cilia are prominent in the respiratory system, brain ependyma and female reproductive tract where they generate a vigorous fluid flow along luminal surfaces. Despite their importance for organ function, how multiciliate cells arise developmentally in diverse epithelia is poorly understood. We identified a novel coiled-coil protein, we have termed multicilin (MCI), whose expression is Notch regulated and restricted to epithelia where multiciliate cells form in Xenopus embryos. In order to identify early downstream targets of multicilin we blocked the formation of endogenous multiciliate cells by injecting ICD mRNA. In a subset of samples we then misexpressed a dexamethasone inducible form of MCI (MCI-HGR) to identify specific targets of MCI in explants of Xenopus epithelium. In explants expressing MCI-HGR genes specifically expressed in ciliated cells such as FoxJ1 and alpha-tubulin were highly upregulated along with various genes known to be required for ciliogenesis, and a large number of genes likely to be part of the ciliome based on homology of potential structural motifs.

2012-03-01 | GSE32452 | GEO

Building a fission machine--structural insights into dynamin assembly and activation.

Project description:Dynamin is a large multidomain GTPase that assembles into helical arrays around the necks of deeply invaginated clathrin-coated pits and catalyzes membrane fission during the final stages of endocytosis. Although it is well established that the function of dynamin in vivo depends on its oligomerization and its capacity for efficient GTP hydrolysis, the molecular mechanisms governing these activities have remained poorly defined. In recent years, there has been an explosion of structural data that has provided new insights into the architecture, organization and nucleotide-dependent conformational changes of the dynamin fission machine. Here, we review the key findings of these efforts and discuss the implications of each with regard to GTP hydrolysis, dynamin assembly and membrane fission.

| S-EPMC4067269 | biostudies-literature

Multicilin promotes centriole assembly and ciliogenesis during multiciliate cell differentiation.

2012-03-01 | E-GEOD-32452 | biostudies-arrayexpress

Molecular basis promoting centriole triplet microtubule assembly.

Project description:The triplet microtubule, a core structure of centrioles crucial for the organization of centrosomes, cilia, and flagella, consists of unclosed incomplete microtubules. The mechanisms of its assembly represent a fundamental open question in biology. Here, we discover that the ciliopathy protein HYLS1 and the β-tubulin isotype TUBB promote centriole triplet microtubule assembly. HYLS1 or a C-terminal tail truncated version of TUBB generates tubulin-based superstructures composed of centriole-like incomplete microtubule chains when overexpressed in human cells. AlphaFold-based structural models and mutagenesis analyses further suggest that the ciliopathy-related residue D211 of HYLS1 physically traps the wobbling C-terminal tail of TUBB, thereby suppressing its inhibitory role in the initiation of the incomplete microtubule assembly. Overall, our findings provide molecular insights into the biogenesis of atypical microtubule architectures conserved for over a billion years.

| S-EPMC10960023 | biostudies-literature

Self-assembling SAS-6 multimer is a core centriole building block.

Project description:Centrioles are conserved microtubule-based organelles with 9-fold symmetry that are essential for cilia and mitotic spindle formation. A conserved structure at the onset of centriole assembly is a "cartwheel" with 9-fold radial symmetry and a central tubule in its core. It remains unclear how the cartwheel is formed. The conserved centriole protein, SAS-6, is a cartwheel component that functions early in centriole formation. Here, combining biochemistry and electron microscopy, we characterize SAS-6 and show that it self-assembles into stable tetramers, which serve as building blocks for the central tubule. These results suggest that SAS-6 self-assembly may be an initial step in the formation of the cartwheel that provides the 9-fold symmetry. Electron microscopy of centrosomes identified 25-nm central tubules with repeating subunits and show that SAS-6 concentrates at the core of the cartwheel. Recombinant and native SAS-6 self-oligomerizes into tetramers with approximately 6-nm subunits, and these tetramers are components of the centrosome, suggesting that tetramers are the building blocks of the central tubule. This is further supported by the observation that elevated levels of SAS-6 in Drosophila cells resulted in higher order structures resembling central tubule morphology. Finally, in the presence of embryonic extract, SAS-6 tetramers assembled into high density complexes, providing a starting point for the eventual in vitro reconstruction of centrioles.

| S-EPMC2838298 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data