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Trisomy 21, the cause of Down syndrome, causes a 0.5-fold protein increase of the chromosome 21-resident gene Pericentrin (PCNT) and reduces primary cilia formation and signaling. Here we investigate the mechanisms by which PCNT imbalances disrupt cilia. Using isogenic RPE-1 cells with increased chromosome 21 dosage, we find PCNT protein accumulates around the centrosome as a pericentrosomal cluster of enlarged cytoplasmic puncta that localize along and at MT ends. Cytoplasmic PCNT puncta impact the intracellular MT trafficking network required for primary cilia, as the PCNT puncta sequester cargo peripheral to centrosomes in what we call pericentrosomal crowding. The centriolar satellite proteins, PCM1, CEP131 and CEP290, important for ciliogenesis, accumulate at sites of enlarged PCNT puncta in trisomy 21 cells. Reducing PCNT when chromosome 21 ploidy is elevated is sufficient to decrease PCNT puncta, reestablish a normal density of MTs around the centrosome, restore ciliogenesis to wild type levels and decrease pericentrosomal crowding. A transient reduction in MTs also decreases pericentrosomal crowding and partially rescues ciliogenesis in trisomy 21 cells, indicating that increased PCNT leads to defects in the microtubule network deleterious to normal centriolar satellite distribution. We propose that chromosome 21 aneuploidy disrupts MT-dependent intracellular trafficking required for primary cilia.TOCMcCurdy et al explore why elevated Pericentrin in trisomy 21 negatively impacts primary cilia formation and signaling. They find that elevated Pericentrin produces more pericentrosomal puncta that associates with and increases microtubules. Changes to Pericentrin and microtubules mislocalizes centriolar satellites in a pericentrosomal crowd.

The neuronal primary cilium and centriolar satellites have functions in neurogenesis, but little is known about their roles in the postnatal brain. We show that ablation of pericentriolar material 1 in the mouse leads to progressive ciliary, anatomical, psychomotor, and cognitive abnormalities. RNAseq reveals changes in amine- and G-protein coupled receptor pathways. The physiological relevance of this phenotype is supported by decreased available dopamine D2 receptor (D2R) levels and the failure of antipsychotic drugs to rescue adult behavioral defects. Immunoprecipitations show an association with Pcm1 and D2Rs. Finally, we sequence PCM1 in two human cohorts with severe schizophrenia. Systematic modeling of all discovered rare alleles by zebrafish in vivo complementation reveals an enrichment for pathogenic alleles. Our data emphasize a role for the pericentriolar material in the postnatal brain, with progressive degenerative ciliary and behavioral phenotypes; and they support a contributory role for PCM1 in some individuals diagnosed with schizophrenia., The role of ciliary/centriolar components in the postnatal brain is unclear. Here, the authors show via ablation of Pcm1 in mice that degenerative ciliary/centriolar phenotypes induce neuroanatomical and behavioral changes. Sequencing of PCM1 in human cohorts and zebrafish in vivo complementation suggests PCM1 mutations can contribute to schizophrenia.

PCM1-JAK2 fusion mutations are rare variants that activate a tyrosine kinase leading to a variety of neoplasms that can involve any hematologic cell line. They most often present as myelodysplasia (MPD) and can demonstrate prominent eosinophilia and/or erythrodysplasia. Transformation to acute leukemia is often seen, as is de novo leukemia. Lymphomas have also been reported. The diagnosis can often be made with routine cytogenetic analysis but specific probes and detailed next generation sequencing may be necessary. JAK2 inhibitors are active in MPD as is stem cell transplantation. Transplantation has occasionally been successful in leukemic phase as well. The current case highlights both the difficulties in diagnosis as well as the second successful treatment of MPD, transformed into acute lymphoblastic leukemia.

Background Global transcriptional profiling of individual cells represents a powerful approach to systematically survey contributions from cell-specific molecular phenotypes to human disease states but requires tissue-specific protocols. Here we sought to comprehensively evaluate protocols for single cell isolation and transcriptional profiling from heart tissue, focusing particularly on frozen tissue which is necessary for study of human hearts at scale. Methods and results Using flow cytometry and high-content screening, we found that enzymatic dissociation of fresh murine heart tissue resulted in a sufficient yield of intact cells while for frozen murine or human heart resulted in low-quality cell suspensions across a range of protocols. These findings were consistent across enzymatic digestion protocols and whether samples were snap-frozen or treated with RNA-stabilizing agents before freezing. In contrast, we show that isolation of cardiac nuclei from frozen hearts results in a high yield of intact nuclei, and leverage expression arrays to show that nuclear transcriptomes reliably represent the cytoplasmic and whole-cell transcriptomes of the major cardiac cell types. Furthermore, coupling of nuclear isolation to PCM1-gated flow cytometry facilitated specific cardiomyocyte depletion, expanding resolution of the cardiac transcriptome beyond bulk tissue transcriptomes which were most strongly correlated with PCM1+ transcriptomes (r = 0.8). We applied these methods to generate a transcriptional catalogue of human cardiac cells by droplet-based RNA-sequencing of 8,460 nuclei from which cellular identities were inferred. Reproducibility of identified clusters was confirmed in an independent biopsy (4,760 additional PCM1- nuclei) from the same human heart. Conclusion Our results confirm the validity of single-nucleus but not single-cell isolation for transcriptional profiling of individual cells from frozen heart tissue, and establishes PCM1-gating as an efficient tool for cardiomyocyte depletion. In addition, our results provide a perspective of cell types inferred from single-nucleus transcriptomes that are present in an adult human heart., Human; Heart; Single cell; Transcriptomics; Methods; Protocol; Transcriptome; Health sciences; Cardiology; Cardiovascular System

Centromere-associated protein-E (CENP-E) is a kinesin motor localizing at kinetochores. Although its mitotic functions have been well studied, it has been challenging to investigate direct consequences of CENP-E removal using conventional methods because CENP-E depletion resulted in mitotic arrest. In this study, we harnessed an auxin-inducible degron system to achieve acute degradation of CENP-E. We revealed a kinetochore-independent role for CENP-E that removes pericentriolar material 1 (PCM1) from centrosomes in late S/early G2 phase. After acute loss of CENP-E, centrosomal Polo-like kinase 1 (Plk1) localization is abrogated through accumulation of PCM1, resulting in aberrant phosphorylation and destabilization of centrosomes, which triggers shortened astral microtubules and oblique cell divisions. Furthermore, we also observed centrosome and cell division defects in cells from a microcephaly patient with mutations in CENPE. Orientation of cell division is deregulated in some microcephalic patients, and our unanticipated findings provide additional insights into how microcephaly can result from centrosomal defects., Owa and Dynlacht employ an auxin-inducible degron system to achieve acute degradation of CENP-E. As a result, the authors reveal a kinetochore-independent role for CENP-E that removes PCM1 from centrosomes in interphase, with implications in microcephaly.

Introduction: MLN-eo associated with gene rearrangements of PDGFRA, PDGFRB, FGFR1, or PCM1-JAK2 are rare haematological neoplasms primarily affecting adults. Eosinophilia commonly occurs but may also be absent. The heterogeneous clinical picture and the rarity of the disease, especially in children, may delay an early diagnosis. MLN-eo are characterized by constitutive tyrosine kinase activity due to gene fusions. It is thus of prognostic importance to obtain a prompt genetic diagnosis to start a specific therapy. Here we report two female paediatric cases of MLN-eo (6 months and 13 years old at initial diagnosis). Methods: In both cases, bone marrow morphology, karyotyping, fluorescence in-situ hybridization analysis (FISH) via break apart probes (PDGFRB (5q32), FGFR1 (8p12), JAK2 (9p24), FIP1L1/CHIC2/PDGFRA (4q12)), targeted RNA sequencing and in one case array CGH were performed. Results: The 6 months old girl was admitted to hospital with a 3-month history of rash and leukocytosis with eosinophilia. The skin showed multiple purpuric lesions (Fig 1 A/B). Mild splenomegaly was noted. White blood count (WBC) was 48000/µl with 38% eosinophils. Bone marrow trephine showed hypercellular marrow with mild fibrosis and eosinophilia without increase in blasts. Biopsy of a skin nodule displayed a histological pattern of interface dermatitis with eosinophilic infiltrate. (Fig 1 C/D). Fluorescence R-banding showed a normal karyotype (46,XX) (Fig. 2 A). However, FISH and array CGH detected an interstitial deletion of 5` PDGFRB (5q32) in 61 % of interphase nuclei (Fig. 2 B-D). Targeted RNA sequencing (RNA-seq) confirmed, as the array CGH suggested, the suspected TNIP1/PDGFRB fusion. According to the WHO criteria, diagnosis of a myeloid neoplasia with PDGFRB rearrangement due to an interstitial deletion in 5q was made. Because of the PDGFRB rearrangement, imatinib (250 mg/m²/d) therapy was started. Leukocyte and eosinophil counts normalized within 4 days without signs of tumour lysis. Skin lesions disappeared within 2 weeks. After 4 weeks, the dose was reduced to 100 mg/m² 3 x/week. Now at 14 months of age, peripheral counts continue to be normal and the fusion transcript is not detectable in the peripheral blood. The 13 years old girl was admitted with severe tachypnoea due to pleural effusions, hepatosplenomegaly and lymphadenopathy. Echocardiography showed endocarditis, left ventricular fibrosis and mitral insufficiency. WBC was 112170 /µL with 39% eosinophils. Bone marrow aspirate and trephine showed a feature of myeloproliferative neoplasia (MPN) with eosinophilia. The karyotype was normal. A rearrangement involving the FGFR1 locus was detected by FISH (Fig. 3 B/C). Splitting of the probe signals indicated an inversion on chromosome 8. Targeted RNA sequencing revealed a PCM1-FGFR1 fusion transcript. Diagnosis of a MLN-eo with FGFR1 rearrangement and evidence of a PCM1-FGFR1 fusion, most likely caused by an inversion on chromosome 8, was made. The girl stabilized after therapy with prednisone, vincristine, hydroxycarbamide and anti-IL-5 antibody. Peripheral blood counts normalized within 2 weeks. Eight weeks after initial diagnosis she presented with signs of a transient ischemic attack, respiratory distress and arterial hypotension. At that time WBC was 139000/µl with 53% myeloid blasts and 5% eosinophils. Trisomy 8 was detected in all metaphases and 88% of cells in FISH (Fig.3 A-C). Diagnosis of a progression to a myeloid blast phase was made. Induction chemotherapy (cytarabine, idarubicin, etoposidphosphate) was administered. On day +22 bone marrow aspirates showed the persisting picture of MPN. Preparations for hematopoietic stem cell transplantation (HSCT) and ponatinib therapy were begun, but cardiac and respiratory insufficiency that developed during chemotherapy were fatal. Conclusion: As these two cases have shown, standard cytogenetic and molecular methods may not be sufficient to diagnose MLN-eo due to cytogenetically cryptic aberrations. Thus, genetic diagnosis must be precise and quick (e.g. break apart FISH, targeted RNA-seq) in order to initiate adequate therapies with tyrosine kinase inhibitors or HSCT. Patients with rearrangements of PDGFRA or PDGFRB usually respond well to imatinib, whereas patients with FGFR1 and JAK2 gene fusions exhibit more aggressive diseases with variable sensitivity to tyrosine kinase inhibitors and have an early indication for HSCT. Figure 1 Figure 1. Disclosures Reiter: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Research Funding; Blueprint Medicines: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses; Incyte: Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses; AOP Orphan Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; Deciphera: Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses; Abbvie: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support.

The transport protein particle (TRAPP) complex was initially identified as a tethering factor for COPII vesicle. Subsequently, three forms (TRAPPI, II, and III) have been found and TRAPPIII has been reported to serve as a regulator in autophagy. This study investigates a new role of mammalian TRAPPIII in ciliogenesis. We found a ciliopathy protein, oral-facial-digital syndrome 1 (OFD1), interacting with the TRAPPIII-specific subunits TRAPPC8 and TRAPPC12. TRAPPC8 is necessary for the association of OFD1 with pericentriolar material 1 (PCM1). Its depletion reduces the extent of colocalized signals between OFD1 and PCM1, but does not compromise the structural integrity of centriolar satellites. The interaction between TRAPPC8 and OFD1 inhibits that between OFD1 and TRAPPC12, suggesting different roles of TRAPPIII-specific subunits in ciliogenesis and explaining the differences in cilium lengths in TRAPPC8-depleted and TRAPPC12-depleted hTERT-RPE1 cells. On the other hand, TRAPPC12 depletion causes increased ciliary length because TRAPPC12 is required for the disassembly of primary cilia. Overall, this study has revealed different roles of TRAPPC8 and TRAPPC12 in the assembly of centriolar satellites and demonstrated a possible tethering role of TRAPPIII during ciliogenesis.

Although centrosome abnormalities are frequent in cancer, the mechanisms responsible for their accumulation are poorly understood. Here we comment on our recent publication identifying a new type of selective autophagy, named doryphagy, which preserves centrosome organization through targeting Centriolar Satellites (CS). Thus, doryphagy prevents inaccurate mitosis and genomic instability.

Global transcriptional profiling of individual cells represents a powerful approach to systematically survey contributions from specific cellular phenotypes to human disease states. Heart diseases are the leading causes of death globally, yet no protocols for robust single cell isolation from adult human hearts have been published. Here, we found that enzymatic dissociation of human heart resulted in low-quality cell suspensions across a range of protocols. We show that isolation of cardiac nuclei provides a robust alternative, and that nuclear transcriptomes reliably represent the cytoplasmic and whole-cell transcriptomes of major cardiac cell types. Furthermore, coupling of nuclear isolation to PCM1-gated flow cytometry facilitated specific cardiomyocyte depletion, expanding the cardiac transcriptome beyond bulk tissue transcriptomes which were strongly correlated with PCM1+ transcriptomes (r=0.8). We applied these methods to generate a transcriptional catalogue of human cardiac cells by droplet-based RNA-sequencing of 8,460 nuclei from which cellular identities were inferred. Reproducibility was explored in an independent biopsy (4,760 additional nuclei) from the same human heart. Our results provide a perspective of the cellular composition of the adult human heart and validate a framework for assessment of cellular individuality across cardiac disease states.

Autophagy is an essential cellular quality control process that has emerged as a critical one for vascular homeostasis. Here, we show that trichoplein (TCHP) links autophagy with endothelial cell (EC) function. TCHP localizes to centriolar satellites, where it binds and stabilizes PCM1. Loss of TCHP leads to delocalization and proteasome‐dependent degradation of PCM1, further resulting in degradation of PCM1's binding partner GABARAP. Autophagic flux under basal conditions is impaired in THCP‐depleted ECs, and SQSTM1/p62 (p62) accumulates. We further show that TCHP promotes autophagosome maturation and efficient clearance of p62 within lysosomes, without affecting their degradative capacity. Reduced TCHP and high p62 levels are detected in primary ECs from patients with coronary artery disease. This phenotype correlates with impaired EC function and can be ameliorated by NF‐κB inhibition. Moreover, Tchp knock‐out mice accumulate of p62 in the heart and cardiac vessels correlating with reduced cardiac vascularization. Taken together, our data reveal that TCHP regulates endothelial cell function via an autophagy‐mediated mechanism., The interaction of TCHP with PCM1 regulates basal autophagy through controlling GABARAP stability. Loss of TCHP function results in impaired autophagy, the accumulation of SQSTM1/p62 and endothelial dysfunction.

The centrosome is a cytoplasmic nonenveloped organelle functioning as one of the microtubule-organizing centers and composing a centriole center surrounded by pericentriolar material (PCM) granules. PCM consists of many centrosomal proteins, including PCM1 and centrosomal protein 131 (CEP131), and helps maintain centrosome stability. Zika virus (ZIKV) is a flavivirus of the family Flaviviridae whose RNA and viral particles are replicated in the cytoplasm. However, how ZIKV interacts with host cell components during its productive infection stage is incompletely understood. Here, using several primate cell lines, we report that ZIKV infection disrupts and disperses the PCM granules. We demonstrate that PCM1- and CEP131-containing granules are dispersed in ZIKV-infected cells, whereas the centrioles remain intact. We found that ZIKV does not significantly alter cellular skeletal proteins, and, hence, these proteins may not be involved in the interaction between ZIKV and centrosomal proteins. Moreover, ZIKV infection decreased PCM1 and CEP131 protein, but not mRNA, levels. We further found that the protease inhibitor MG132 prevents the decrease in PCM1 and CEP131 levels and centriolar satellite dispersion. Therefore, we hypothesized that ZIKV infection induces proteasomal PCM1 and CEP131 degradation and thereby disrupts the PCM granules. Supporting this hypothesis, we show that ZIKV infection increases levels of mind bomb 1 (MIB1), previously demonstrated to be an E3 ubiquitin ligase for PCM1 and CEP131 and that ZIKV fails to degrade or disperse PCM in MIB1-ko cells. Our results imply that ZIKV infection activates MIB1-mediated ubiquitination that degrades PCM1 and CEP131, leading to PCM granule dispersion.

The recent years have seen a drastic increase in the amount of available genomic sequences. Alongside this explosion, hundreds of computational tools were developed to assess the impact of observed genetic variation. Critical Assessment of Genome Interpretation (CAGI) provides a platform to evaluate the performance of these tools in experimentally relevant contexts. In the CAGI-5 challenge assessing the 38 missense variants affecting the human Pericentriolar Material 1 protein (PCM1), our SNAP-based submission was the top performer, although it did worse than expected from other evaluations. Here, we compare the CAGI-5 submissions, and 24 additional commonly used variant effect predictors, to analyze the reasons for this observation. We identified per residue conservation, structural, and functional PCM1 characteristics, which may be responsible. As expected, predictors had a hard time distinguishing effect variants in non-conserved positions. They were also better able to call effect variants in a structurally rich region than in a less-structured one; in the latter, they more often correctly identified benign than effect variants. Curiously, most of the protein was predicted to be functionally robust to mutation – a feature that likely makes it a harder problem for generalized variant effect predictors.

Nup188 is part of the nuclear pore complex scaffold that is specifically required for heart development. As shown by Vishnoi et al., Nup188 also moonlights as a centrosome protein by binding directly to Cep152 and contributing to centriole duplication., NUP188 encodes a scaffold component of the nuclear pore complex (NPC) and has been implicated as a congenital heart disease gene through an ill-defined function at centrioles. Here, we explore the mechanisms that physically and functionally segregate Nup188 between the pericentriolar material (PCM) and NPCs. Pulse-chase fluorescent labeling indicates that Nup188 populates centrosomes with newly synthesized protein that does not exchange with NPCs even after mitotic NPC breakdown. In addition, the steady-state levels of Nup188 are controlled by the sensitivity of the PCM pool, but not the NPC pool, to proteasomal degradation. Proximity-labeling and super-resolution microscopy show that Nup188 is vicinal to the inner core of the interphase centrosome. Consistent with this, we demonstrate direct binding between Nup188 and Cep152. We further show that Nup188 functions in centriole duplication at or upstream of Sas6 loading. Together, our data establish Nup188 as a component of PCM needed to duplicate the centriole with implications for congenital heart disease mechanisms.

Centrioles are core structural elements of both centrosomes and cilia. Although cytoplasmic granules called centriolar satellites have been observed around these structures, lack of a comprehensive inventory of satellite proteins impedes our understanding of their ancestry. To address this, we performed mass spectrometry (MS)‐based proteome profiling of centriolar satellites obtained by affinity purification of their key constituent, PCM1, from sucrose gradient fractions. We defined an interactome consisting of 223 proteins, which showed striking enrichment in centrosome components. The proteome also contained new structural and regulatory factors with roles in ciliogenesis. Quantitative MS on whole‐cell and centriolar satellite proteomes of acentriolar cells was performed to reveal dependencies of satellite composition on intact centrosomes. Although most components remained associated with PCM1 in acentriolar cells, reduced cytoplasmic and satellite levels were observed for a subset of centrosomal proteins. These results demonstrate that centriolar satellites and centrosomes form independently but share a substantial fraction of their proteomes. Dynamic exchange of proteins between these organelles could facilitate their adaptation to changing cellular environments during development, stress response and tissue homeostasis.

Autophagy is an essential cellular quality control process that emerged critical for vascular homeostasis. Here we describe, the role for Trichoplein (TCHP) protein in linking autophagy with endothelial cells (ECs) function. The depletion of TCHP in ECs impairs migration and sprouting. TCHP directly binds PCM1, to regulate degradation of GABARAP, thus leading to a defective autophagy. Mechanistically, TCHP is indispensable for autophagosome maturation and its depletion resulted in the accumulation of SQSTM1/p62 (p62) and unfolded protein aggregates in ECs. The latter process is coupled to TCHP-mediated NF-kB activation. Of note, low levels of TCHP and high p62 levels were detected in primary ECs from patients with coronary artery disease. In addition, Tchp knock-out mice showed accumulation of p62 in the heart and cardiac vessels and reduced cardiac vascularization. Here, we reveal an autophagy-mediated mechanism for TCHP down-regulation, which poses a plausible target for regulation of endothelial function.

Introduction Ageing is associated with an attenuated hypertrophic response to resistance training and periods of training interruptions. Hence, elderly would benefit from the ‘muscle memory’ effects of resistance training on muscle strength and mass during detraining and retraining. As the underlying mechanisms are not yet clear, this study investigated the role of myonuclei during training, detraining and retraining by using PCM1 labelling in muscle cross-sections of six older men. Methods Knee extension strength and power were measured in 30 older men and 10 controls before and after 12 weeks resistance training and after detraining and retraining of similar length. In a subset, muscle biopsies from the vastus lateralis were taken for analysis of fibre size, fibre type distribution, Pax7+ satellite cell number and myonuclear domain size. Results Resistance training increased knee extension strength and power parameters (+10 to +36%, p < .001) and decreased the frequency of type IIax fibres by half (from 20 to 10%, p = .034). Detraining resulted in a modest loss of strength and power (−5 to −15%, p ≤ .004) and a trend towards a fibre-type specific decrease in type II fibre cross-sectional area (−17%, p = .087), type II satellite cell number (−30%, p = .054) and type II myonuclear number (−12%, p = .084). Less than eight weeks of retraining were needed to reach the post-training level of one-repetition maximum strength. Twelve weeks of retraining were associated with type II fibre hypertrophy (+29%, p = .050), which also promoted an increase in the number of satellite cells (+72%, p = .036) and myonuclei (+13%, p = .048) in type II fibres. Changes in the type II fibre cross-sectional area were positively correlated with changes in the myonuclear number (Pearson's r between 0.40 and 0.73), resulting in a stable myonuclear domain. Conclusion Gained strength and power and fibre type changes were partially preserved following 12 weeks of detraining, allowing for a fast recovery of the 1RM performance following retraining. Myonuclear number tended to follow individual changes in type II fibre size, which is in support of the myonuclear domain theory., Experimental Gerontology, 133

International audience; During cerebellar development, granule neuron progenitors (GNPs) proliferate by transducing Sonic Hedgehog (SHH) signaling via the primary cilium. Precise regulation of ciliogenesis, thus, ensures proper GNP pool expansion. Here, we report that Atoh1, a transcription factor required for GNPs formation, controls the presence of primary cilia, maintaining GNPs responsiveness to SHH. Loss of primary cilia abolishes the ability of Atoh1 to keep GNPs in a proliferative state. Mechanistically, Atoh1 promotes ciliogenesis by transcriptionally regulating Cep131, which facilitates centriolar satellite (CS) clustering to the basal body. Importantly, ectopic expression of Cep131 counteracts the effects of Atoh1 loss in GNPs by restoring proper localization of CS and ciliogenesis. This Atoh1-CS-primary cilium-SHH pro-proliferative pathway is also conserved in SHH-type medulloblastoma, a pediatric brain tumor arising from the GNPs. Together, our data reveal how Atoh1 modulates the primary cilium to regulate GNPs development.

The centrosome is the master orchestrator of mitotic spindle formation and chromosome segregation in animal cells. Centrosome abnormalities are frequently observed in cancer, but little is known of their origin and about pathways affecting centrosome homeostasis. Here we show that autophagy preserves centrosome organization and stability through selective turnover of centriolar satellite components, a process we termed doryphagy. Autophagy targets the satellite organizer PCM1 by interacting with GABARAPs via a C-terminal LIR motif. Accordingly, autophagy deficiency results in accumulation of large abnormal centriolar satellites and a resultant dysregulation of centrosome composition. These alterations have critical impact on centrosome stability and lead to mitotic centrosome fragmentation and unbalanced chromosome segregation. Our findings identify doryphagy as an important centrosome-regulating pathway and bring mechanistic insights to the link between autophagy dysfunction and chromosomal instability. In addition, we highlight the vital role of centriolar satellites in maintaining centrosome integrity., Centrosomes drive mitotic spindle formation and chromosome segregation. Here, the authors show that centrosome stability is regulated by selective autophagic degradation of centriolar satellite components in a process they term doryphagy, connecting autophagy and chromosomal integrity.

Centriolar satellites are ubiquitous in vertebrate cells. They have recently emerged as key regulators of centrosome/cilium biogenesis, and their mutations are linked to ciliopathies. However, their precise functions and mechanisms of action, which potentially differ between cell types, remain poorly understood. Here, we generated retinal pigmental and kidney epithelial cells lacking satellites by genetically ablating PCM1 to investigate their functions. While satellites were essential for cilium assembly in retinal epithelial cells, kidney epithelial cells lacking satellites still formed full-length cilia but at significantly lower levels, with reduced centrosomal levels of key ciliogenesis factors. Using these cells, we identified the first satellite-specific functions at cilia, specifically in regulating ciliary content, Hedgehog signalling, and epithelial cell organization. However, other satellite-linked functions, namely proliferation, cell cycle progression and centriole duplication, were unaffected in these cells. Quantitative transcriptomic and proteomic profiling revealed that loss of satellites scarcely affects transcription, but significantly alters the proteome, particularly actin cytoskeleton pathways and neuronal functions. Together, our findings identify cell type-specific roles for satellites and provide insight into the phenotypic heterogeneity of ciliopathies.