An actin filament branching surveillance system regulates cell cycle progression, cytokinesis and primary ciliogenesis
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA933541 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR23392270_1.fastq.gz | Fastqsanger.gz | |||
| SRR23392270_2.fastq.gz | Fastqsanger.gz | |||
| SRR23392271_1.fastq.gz | Fastqsanger.gz | |||
| SRR23392271_2.fastq.gz | Fastqsanger.gz | |||
| SRR23392272_1.fastq.gz | Fastqsanger.gz |
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Project description:Dysfunction of cell cycle control and defects of primary ciliogenesis are two features of many cancers. Whether these events are interconnected and the driving mechanism controlling and coordinating these events remains largely unknown. Here we identified an actin branching surveillance system that alerts cells for the insufficiency of the actin branching network controlling the restriction point, cytokinesis， and primary ciliogenesis. We found that the ciliopathy protein Oral-Facial-Digital syndrome 1 (OFD1) functions as a previously undescribed class II NPF to promote Arp2/3 complex-mediated actin branching synergistically with class I NPF via its C-terminal acidic domain. Perturbation of actin branching promotes OFD1 degradation and inactivation via a liquid-to-gel transition at centriolar satellites. Elimination of OFD1 or disruption of OFD1-Arp2/3 interaction promotes ciliogenesis and drives proliferating, non-transformed cells into quiescence by an RB-dependent mechanism that is independent of ciliogenesis, senescence, or centrosome loss, which could be reversed by oncogene overactivation. Oncogene-transformed cells, as well as most cancer cells, bypass the G1/S checkpoint in the absence of OFD1 but fail to assemble actin filaments on the actomyosin ring, resulting in incomplete cytokinesis and irreversible mitotic catastrophe. Inhibition of OFD1 leads to marked suppression of pancreatic, colon, and triple-negative breast cancer cell growth in mouse xenograft models. Thus, cancer cells display a major difference from normal cells in their response to the OFD1-mediated actin branching surveillance system, and targeting this surveillance system provides a new direction for cancer therapy.
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Project description:The deep-branching protozoan parasite Giardia lamblia is the causative agent of the intestinal disease giardiasis. Consistent with its proposed evolutionary position, many pathways are minimalistic or divergent, including its actin cytoskeleton. Giardia is the only eukaryote known to lack all canonical actin-binding proteins. Previously, our lab identified a number of non-canonical Giardia lamblia actin (GlActin) interactors; however, these proteins appeared to interact only with monomeric or globular actin (G-actin), rather than filamentous actin (F-actin). To identify interactors, we used a chemical crosslinker to preserve native interactions, followed by an anti-GlActin antibody, Protein A affinity chromatography, and liquid chromatography coupled to mass spectrometry. We found 46 putative actin interactors enriched in the conditions favoring F-actin. None of the proteins identified contain known actin-interacting motifs, and many lacked conserved domains. Each potential interactor was then tagged with the fluorescent protein mNeonGreen and visualized in live cells. We categorized the proteins based on their primary localization; localizations included ventral disc, marginal plate, nuclei, flagella, plasma membrane, and internal membranes. One protein from each category was co-localized with GlActin using immunofluorescence microscopy. We also co-immunoprecipitated one protein from each category and confirmed three interactions. Most of the localization patterns are consistent with previously demonstrated GlActin functions, but the ventral disc represents a new category of actin interactor localization. These results suggest a role for GlActin in ventral disc function, which has previously been controversial.
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Project description:Mammalian cardiomyocytes lose the ability to proliferate shortly after birth. This accounts for the limited regeneration capacity of the mammalian heart. A characteristic feature of growth arrested cardiomyocytes is binucleation, but the molecular mechanisms are not well understood. In rodents, binucleation of cardiomyocytes starts after birth and occurs through incomplete cytokinesis. Here we demonstrate an important and unexpected role of GAS2L3, a recently identified actin and tubulin binding protein, for cardiomyocyte cytokinesis during heart development in mice. Mice deficient in GAS2L3 die shortly after birth due to dilated cardiomyopathy. Cardiomyocyte-specific deletion of GAS2L3 confirmed that the phenotype resulted from the loss of GAS2L3 in cardiomyocytes. We show that a deficiency in GAS2L3 leads to a strong reduction in cardiomyocyte numbers due to reduced proliferation. In addition, the loss of Gas2l3 resulted in premature binucleation of cardiomyocytes and in induction of a p53-transcriptional program including the cell cycle inhibitor p21. Collectively, these data identify an important role for GAS2L3 in cardiomyocyte cytokinesis during development.
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