Structural mechanisms for centrosomal recruitment and organization of the microtubule nucleator γ-TuRC

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: March 12, 2025

Abstract The γ-tubulin ring complex (γ-TuRC) acts as a structural template for microtubule formation at centrosomes, associating with two main compartments: the pericentriolar material and centriole lumen. In material, γ-TuRC is involved in organization, while function of lumenal pool remains unclear. conformational landscape γ-TuRC, which crucial its activity, centrosomal anchoring mechanisms, determine activity turnover, are not understood. Using cryo-electron tomography, we analyze γ-TuRCs human cells purified centrosomes. Pericentriolar simultaneously associate essential adapter NEDD1 microcephaly protein CDK5RAP2. forms tetrameric structure base through interactions four GCP3/MZT1 modules GCP5/6-specific extensions, multiple copies CDK5RAP2 engage distinct binding patterns to promote closure activation. lumen, branching factor Augmin tethers condensed cluster wall defined directional orientation. Centriole-lumenal γ-TuRC-Augmin protected from degradation during interphase released mitosis aid chromosome alignment. This study provides unique view on molecular organization centrosomes identifies an important cellular centriole-lumenal γ-TuRCs.

Language: Английский

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Centriolar cap proteins CP110 and CPAP control slow elongation of microtubule plus ends

The Journal of Cell Biology, Journal Year: 2025, Volume and Issue: 224(3)

Published: Jan. 23, 2025

Centrioles are microtubule-based organelles required for the formation of centrosomes and cilia. Centriolar microtubules, unlike their cytosolic counterparts, stable grow very slowly, but underlying mechanisms poorly understood. Here, we reconstituted in vitro interplay between proteins that cap distal centriole ends control elongation: CP110, CEP97, CPAP/SAS-4. We found whereas CEP97 does not bind to microtubules directly, CP110 autonomously binds microtubule plus ends, blocks growth, inhibits depolymerization. Cryo-electron tomography revealed associates with luminal side suppresses protofilament flaring. directly interacts CPAP, which acts as a polymerase overcomes CP110-induced growth inhibition. Together, two impose extremely slow processive growth. Disruption CP110–CPAP interaction cells elongation increases incidence defects. Our findings reveal how centriolar opposing activities regulate plus-end explain antagonistic relationship during formation.

Language: Английский

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An interaction network of inner centriole proteins organised by POC1A-POC1B heterodimer crosslinks ensures centriolar integrity

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Nov. 14, 2024

Abstract Centriole integrity, vital for cilia formation and chromosome segregation, is crucial human health. The inner scaffold within the centriole lumen composed of proteins POC1B, POC5 FAM161A key to this integrity. Here, we provide an understanding function proteins. We demonstrate importance interaction network organised by POC1A-POC1B heterodimers lumen, where WD40 domain POC1B localises close wall, while POC5-interacting POC1A resides in lumen. POC1A-POC5 tetramerization are essential stability. microtubule binding MDM1 POC1A-POC1B, likely positioning tetramer near wall. Disruption or leads defects deletion both genes causes disintegration. These findings insights into organisation scaffold.

Language: Английский

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A delta-tubulin/epsilon-tubulin/Ted protein complex is required for centriole architecture

Published: Feb. 6, 2025

Centrioles have a unique, conserved architecture formed by three linked “triplet” microtubules arranged in nine-fold symmetry. The mechanisms which these triplet are not understood and likely involve the noncanonical tubulins delta-tubulin epsilon-tubulin. Previously, we found that human cells deficient or epsilon-tubulin form abnormal centrioles, characterized an absence of microtubules, lack central core protein POC5, futile cycle centriole formation disintegration (Wang et al., 2017). Here, show lacking either associated proteins TEDC1 TEDC2 same phenotypes. Using ultrastructure expansion microscopy, find mutant centrioles elongate to length as control G2-phase. These mutants fail recruit inner scaffold expanded proximal region. During mitosis, further before fragmenting disintegrating. All four physically interact capable forming subcomplex tubulins. results support AlphaFold Multimer model tetramer predicted heterodimer. localize centrosomes mutually dependent on each other for localization. Our demonstrate delta-tubulin, epsilon-tubulin, TEDC1, function together promote robust architecture. This work also lays groundwork future molecular studies this complex, providing basis determining underlie assembly interplay between structure.

Language: Английский

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TRIM37 prevents ectopic spindle pole assembly by peptide motif recognition and substrate-dependent oligomerization

Nature Structural & Molecular Biology, Journal Year: 2025, Volume and Issue: unknown

Published: May 25, 2025

Language: Английский

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Human NLRP3 inflammasome activation leads to formation of condensate at the microtubule organizing center

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 15, 2024

The NLRP3 inflammasome is a multi-protein molecular machine that mediates inflammatory responses in innate immunity. Its dysregulation has been linked to large number of human diseases. Using cryogenic fluorescence-guided focused-ion-beam (cryo-FIB) milling and electron cryo-tomography (cryo-ET), we obtained 3-D images the

Language: Английский

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Charting the landscape of cytoskeletal diversity in microbial eukaryotes

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 18, 2024

Abstract Microbial eukaryotes are small and often resistant to standard labelling imaging techniques, therefore remain understudied – despite their critical ecological importance - with the exception of a few established models. Here, we use Ultrastructure Expansion Microscopy (U-ExM) carry out high-resolution volumetric over 200 cultured planktonic across major lineages. By combining U-ExM pan- specific immuno-labelling, reveal novel microtubule centrin-containing elements assign molecular identities enigmatic cytoskeletal structures observed previously only by electron microscopy. Our investigation represents first systematic survey extensive diversity on display eukaryotic tree, including species groups dinoflagellates, haptophytes, ciliates, euglenids, cryptomonads, green algae. approach extends mixed environmental samples, paving way for cell biology at ultrastructural resolution unprecedented scale, crucial step towards understanding protecting complex ecosystems in face biodiversity loss.

Language: Английский

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BICD2 is a centriolar protein that controls mother-daughter centriole engagement and the licensing of duplication

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 4, 2025

Abstract Centrosomes and the centrioles at their core have key cellular roles that demand they are duplicated exactly once during each cell cycle. Abnormal centriole numbers can contribute to onset of different pathologies thus mechanisms evolved tightly control duplication. Importantly, pairs barred from duplicating until go through a not completely understood process “licensing” includes physical separation mother daughter centrioles. Here we report dynein adaptor BICD2 is centriolar protein has previously unknown dynein-independent role controlling mother-daughter engagement. We show pool resides centrosome, surrounding close centriole. Removal results in premature disengagement G2 early M amplification both non-transformed transformed cells. characterize molecular determinants localization suggest this localization, function centriole, controlled by phosphorylation. Our findings reveal novel BICD2, independent its ability interact with dynein, which crucial for regulation licensing centrosome duplication

Language: Английский

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‘Expansion microscopy’ turns ten: how a tissue-swelling method brought super-resolution imaging to the masses

Nature, Journal Year: 2025, Volume and Issue: 637(8046), P. 752 - 754

Published: Jan. 13, 2025

Language: Английский

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Ciliopathy-associated protein, CEP290, is required for ciliary necklace and outer segment membrane formation in retinal photoreceptors.

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 20, 2025

The most common genetic cause of the childhood blinding disease Leber Congenital Amaurosis is mutation ciliopathy gene CEP290 . Though studied extensively, photoreceptor-specific roles remain unclear. Using advanced microscopy techniques, we investigated sub-ciliary localization and its role in mouse photoreceptors during development. was found throughout connecting cilium between microtubules membrane, with nine-fold symmetry. In absence ciliogenesis occurs, but membrane aberrant, sub-structures, such as ciliary necklace Y-links, are defective or absent mid to distal cilium. Transition zone proteins AHI1 NPHP1 were abnormally restricted proximal CEP290, while others like NPHP8 CEP89 unaffected. Although outer segment disc formation inhibited mutant retina, observed large numbers extracellular vesicles. These results suggest for structure, spatial distribution a subset transition proteins, which collectively lead failure photoreceptor degeneration.

Language: Английский

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