TRIM37 controls cancer-specific vulnerability to PLK4 inhibition.

Centrosomes catalyse the formation of microtubules needed to assemble the mitotic spindle apparatus1. Centrosomes themselves duplicate once per cell cycle, in a process that is controlled by the serine/threonine protein kinase PLK4 (refs. 2,3). When PLK4 is chemically inhibited, cell division proceeds without centrosome duplication, generating centrosome-less cells that exhibit delayed, acentrosomal spindle assembly4. Whether PLK4 inhibitors can be leveraged as a treatment for cancer is not yet clear. Here we show that acentrosomal spindle assembly following PLK4 inhibition depends on levels of the centrosomal ubiquitin ligase TRIM37. Low TRIM37 levels accelerate acentrosomal spindle assembly and improve proliferation following PLK4 inhibition, whereas high TRIM37 levels inhibit acentrosomal spindle assembly, leading to mitotic failure and cessation of proliferation. The Chr17q region containing the TRIM37 gene is frequently amplified in neuroblastoma and in breast cancer5-8, rendering these cancer types highly sensitive to PLK4 inhibition. We find that inactivating TRIM37 improves acentrosomal mitosis because TRIM37 prevents PLK4 from self-assembling into centrosome-independent condensates that serve as ectopic microtubule-organizing centres. By contrast, elevated TRIM37 expression inhibits acentrosomal spindle assembly through a distinct mechanism that involves degradation of the centrosomal component CEP192. Thus, TRIM37 is an essential determinant of mitotic vulnerability to PLK4 inhibition. Linkage of TRIM37 to prevalent cancer-associated genomic changes-including 17q gain in neuroblastoma and 17q23 amplification in breast cancer-may offer an opportunity to use PLK4 inhibition to trigger selective mitotic failure and provide new avenues to treatments for these cancers.

Masticatory performance in oral function assessment: Alternative methods.

BACKGROUND: Masticatory function declines with age or disease, implicating a poor chewing efficiency and an often-unconscious change for a less healthy, yet easy to chew diet. Timely screening of masticatory function may foster an early-onset diagnosis and potential treatment. The aim of this study was to compare alternative diagnostic tools for masticatory function to a Jelly-scan test. MATERIALS AND METHODS: Patients aged 70 years and older who were hospitalised for rehabilitation were recruited for this study. A total of four different tests for masticatory function were administered. The Japanese Society of Gerodontology glucose extraction test (Jelly-scan) was used as reference to compare a colour-changing gum test (Gum1-colour) as well as a mixing ability test with a visual (Gum2-visual) and opto-electronical (Gum2-digital) analyses. Receiver operating characteristic (ROC) curves were used to establish the discriminative value, kappa-values were used to estimate individual agreements and correlations were verified using Spearman's tests. RESULTS: Sixty-one patients (Men n = 23, Women n = 38) aged 82.4 ± 6.8 years participated in the experiments. The average number of natural teeth was 16.5 ± 10.5, 34.4% of the participants wore removable dentures. For all tests, the sum of sensitivity and specificity was >150%. All test correlated with Jelly-scan (absolute Rho >0.5). With Jelly-scan 51 participants (83.6%) were diagnosed with "masticatory hypofunction". After reducing the cut-off value of the test from 100 mg/dL to 65 mg/dL, only 33 participants (54%) fulfilled the diagnosis. This post-hoc analysis increased the sensitivity of the Gum2-tests and the agreement to kappa >0.5 for all three tests. CONCLUSION: All three tests can be considered useful screening alternatives. In its original version, Jelly-scan may tend to over-diagnose masticatory hypofunction, hence a novel cut-off with better agreement between tests is suggested.

Oral Function for Diagnosing Oral Hypofunction in Healthy Young Adults: A Comparison with the Literature.

This study investigated decline in oral function in healthy young adults and compared it with that observed in an earlier studies employing older adults. The participants comprised 130 young healthy adults (mean age 24.1±2.9 yr), all with complete dentition. All participants underwent the oral hypofunction test established by the Japanese Society of Gerodontology, which evaluates oral hygiene, oral dryness, occlusal force, tongue-lip motor function (oral diadochokinetic rate; ODK), tongue pressure, and masticatory and swallowing function. The average value for and rate of hypofunction of each parameter were calculated. In healthy young adults, the scores were 28.9±17.1% for oral hygiene; 28.8±2.2 for oral dryness; 959.9±499.8 N for occlusal force; 7.0±0.8 times/sec for ODK /pa/, 7.6±0.8 times/sec for /ta/, and 6.9±0.9 times/sec for /ka/; 41.8±8.4 kPa for tongue pressure; 249.8±94.1 mg/dl for masticatory function; and 0.2±0.7 for swallowing function. No sign or symptom of change in oral function was observed at a high rate in young adults. Occlusal force, tongue-lip motor function, and tongue pressure showed a large difference in the rate of hypofunction between younger and older adults, however.

Influence of Chewing Gummy Jelly Containing Aroma Compound on Psychological Stress and Autonomic Nervous System Activity: A Randomized Crossover Trial.

The aim of this randomized crossover trial was to clarify the effects of chewing gummy jelly containing a compound of decanoic acid, oligonol, methyl cellulose, and citral (DOMAC) on mental stress and autonomic nervous activity in facemask wearers. A placebo gummy jelly was used in conjunction with DOMAC. Eight healthy adults with no tooth loss (mean age: 35±5 yr) were included. The participants were required to chew one DOMAC or placebo gummy jelly for 5 min after wearing a facemask for 20 min in the laboratory, then the other gummy jelly after a washout period. Rate of change in salivary immunoglobulin A (IgA) as a marker of stress was compared between before and after chewing. Additionally, sympathetic and parasympathetic activity was compared at both time points. A significant difference was observed in the percentage change in salivary IgA from that at before wearing a facemask: 127±34% (mean±standard deviation) while wearing a facemask; 46±20% while chewing DOMAC gummies; and 47±26% while chewing placebo gummies (p<0.05). Parasympathetic nervous system activity was 971.2±1040.7 ms2 at 20 min after facemask wearing; 295.0±253.0 ms2 after DOMAC gummy chewing; and 1956.1±2798.0 ms2 after chewing a placebo gummy jelly; with significant differences only being found between 20 min after facemask wearing and after DOMAC gummy chewing (p<0.05). Sympathetic nervous system activity was 1.80±1.83 at 20 min after facemask wearing; 4.06±3.33 after DOMAC gummy chewing; and 4.95±7.02 after chewing a placebo gummy jelly; with significant differences only being found between 20 min after facemask wearing and after DOMAC gummy chewing. These results suggest that chewing gummy jellies containing DOMAC relieves stress caused by facemask wearing and activates sympathetic nervous system activity.

Oral function and nutritional status in non-acute hospitalised elders.

INTRODUCTION: Malnutrition and risk of malnutrition continues to be a common finding in elders, yet its association with oral function in hospitalised patients remains unclear. MATERIAL AND METHODS: Patients aged 70 years or over who had been hospitalised for non-acute rehabilitation were recruited. Nutritional risk was screened using the Mini-Nutritional Assessment Short Form (MNA-SF) and Nutritional Risk Screening (NRS) scores. Malnutrition was assessed according to the Global Leadership Initiative on Malnutrition (GLIM) criteria. All participants underwent the oral hypofunction test battery, evaluating oral hygiene, oral dryness, occlusal force, tongue-lip motor function, tongue pressure, masticatory and swallowing function. Statistical analyses comprised Mann-Whitney or Kruskal-Wallis tests. Bivariate associations between categorical variables were tested using the Pearson chi-square test; for continuous variables, the Spearman correlation was calculated. A P-value < .05 was considered statistically significant. RESULTS: Sixty patients aged a mean 82.5 ± 7.0 years participated. Some 88.3% were diagnosed with oral hypofunction, and this was more common in older patients (P = .020). Analysing the 7 oral hypofunction tests as an interval variable (NiOF) revealed additional correlations with number of teeth (ρ = 0.477) as well as the nutritional risk, evaluated by the MNA-SF (ρ = -0.284) and NRS (ρ = 0.317) scores. NiOF scores were higher among denture wearers (P = .003). GLIM did not confirm the correlation with NiOF. Biomarkers such as serum albumin and CRP were not associated with the NiOF score. CONCLUSION: In this sample, the association between oral function and nutritional state is more obvious in nutritional risk scores than in the malnutrition diagnosis by GLIM.

HsSAS-6-dependent cartwheel assembly ensures stabilization of centriole intermediates.

At the onset of procentriole formation, a structure called the cartwheel is formed adjacent to the pre-existing centriole. SAS-6 proteins are thought to constitute the hub of the cartwheel structure. However, the exact function of the cartwheel in the process of centriole formation has not been well characterized. In this study, we focused on the functions of human SAS-6 (HsSAS-6, also known as SASS6). By using an in vitro reconstitution system with recombinant HsSAS-6, we first observed its conserved molecular property of forming the central part of the cartwheel structure. Furthermore, we uncovered critical functions of HsSAS-6 by using a combination of an auxin-inducible HsSAS-6-degron (AID) system and super-resolution microscopy in human cells. Our results demonstrate that the HsSAS-6 is required not only for the initiation of centriole formation, but also for the stabilization of centriole intermediates. Moreover, after procentriole formation, HsSAS-6 is necessary for limiting Plk4 accumulation at the centrioles and thereby suppressing the formation of initiation sites that would otherwise promote the development of extra procentrioles. Overall, these findings illustrate the conserved and fundamental functions of the cartwheel in centriole duplication.

Validation of a novel diagnostic tool for decreased tongue pressure.

INTRODUCTION: Reduced tongue pressure may render eating and swallowing difficult. The purpose of this study was to investigate whether the tongue training device can also be used as a diagnostic device and whether its sensitivity and specificity are equal to the numerical tongue pressure measuring device. MATERIAL AND METHODS: The target group is patients aged 70 years and over who are hospitalised for rehabilitation. Tongue pressure was measured by both, a tongue pressure measuring instrument and a tongue training tool. The diagnosis of the reduced tongue pressure was made with the tongue pressure measuring instrument and set the verified with the novel tongue training tool. RESULTS: Sixty-two participants were included in the study. Forty-five were classified by the tongue pressure measuring device and 53 by the tongue training device as 'low tongue pressure'. Spearman correlation confirmed a positive correlation between the tongue pressure measuring device and the tongue training device rs  = 0.800, p = 0.01 level (2-tailed). The tongue training device test identified sensitivity was 100%, and its specificity was 52.9%. The AUC of the ROC curve is 0.901. CONCLUSION: The tongue training device seems a simple, safe and readily available alternative to the tongue pressure measuring device for the diagnosis of low tongue pressure, with an excellent sensitivity and very good specificity.

Effective training duration and frequency for lip-seal training in older people using a self-training instrument.

OBJECTIVE: To determine the effects of the training duration and frequency on lip-seal strength (LSS) in older people. BACKGROUND: Lip-seal is important for speaking, eating and swallowing. LSS decreases after training ends; therefore, continuous training is essential. MATERIALS AND METHODS: Participants underwent the resistance training of LSS. Regarding training duration, eight women aged ≥65 years participated in a crossover study with trainings A (direction: 1, duration: 50 seconds) and B (directions: 3, duration: 3 minutes), daily for 4 weeks. Regarding training frequency, 40 women aged ≥65 years were divided into four groups based on frequency (everyday, every-other-day, once-a-week and control groups), and all groups excluding the control group performed training B for 4 weeks. LSS was measured at weeks 0, 2 and 4 using a digital strain gauge. Friedman's test was used, followed by Steel-Dwass test (α = 0.05). RESULTS: Regarding the effects of the training duration, significant differences in LSS were noted between weeks 0 and 4 for training B, but no difference was noted for training A. Regarding training frequency, significant differences were observed between weeks 0 and 2 or 4 in the everyday and once-a-week groups. Significant differences were observed in the every-other-day group between weeks 0 and 4 and no difference in the control group. For all groups, median LSS was higher in week 2 or 4 than that in week 0. CONCLUSION: Lip-seal training for 3 minutes per session everyday, every-other-day or once-a-week for 4 weeks increased LSS of older people.

Effect of Lip-seal Resistance Training on Lip-seal Strength in Young Adults.

Lip-seal strength is important for articulating bilabials, capturing food during eating, maintaining fluid within the oral cavity before swallowing, and achieving swallowing pressure. The objective of this study was to investigate the effect of lip-seal resistance training on lip-seal strength in young adults. The participants comprised 15 young healthy adults aged 26-34 years, all with complete dentition. Each was required to perform lip-seal resistance training 5 weekdays a week for 4 weeks with a commercially available instrument for that purpose. The instrument was placed on the midline, left corner, and right corner of the mouth, and pulled forward, leftward, and rightward, respectively. The participants were required to pull the training instrument forcefully while resisting by closing the lips together as strongly as possible until the instrument exited the lips. Lip-seal strength was measured at before and after training using a measurement device. Change in lip-seal strength between before and after training was analyzed using the Wilcoxon signed rank test. The mean lip-seal strength was 8.9±1.5 N before training and 10.4±1.8 N after. A significant difference was observed in lip-seal strength between before and after training (p=0.003), and the mean increase during the training period was 18.1±17.6%. The results showed that lip-seal resistance training for 4 weeks increased lip-seal strength in young adults. These findings suggest that training that involves pulling not only in a forward direction, but also in bilateral directions strongly stimulates the orbicularis oris muscle, resulting in an increase in lip-seal strength.

Intra- and Inter-Investigator Reliability of Measurement of Lip-Seal Strength in Adults.

The purpose of this methodological study was to clarify intra- and inter-investigator reliability of lip-seal strength measurement in adults. Lip-seal strength was measured with a digital medical strain gauge using the button-pull method. The coefficient of variation (CV) of intra-investigator reliability of measurement in 24 healthy adult volunteers (16 men, 8 women; mean age, 26±3 years) ranged from 0.088 to 0.103 (mean for 3 investigators, 0.098). The intraclass correlation coefficient (ICC [1,1]) of intra-investigator reliability of this method of lip-seal strength measurement ranged from 0.759 to 0.832 (mean, 0.804). The ICC (2,1) of inter-investigator reliability of the measured values was 0.737. The CV of intra-investigator reliability of lip-seal strength measurement by a single investigator in 54 adult patients (14 men, 40 women; mean age, 49±16 years) was 0.072. The ICC (1,1) of intra-investigator reliability of this measurement method of lip-seal strength was 0.863. A CV of approximately 0.2 or lower is considered to indicate excellent agreement; an ICC of approximately 0.75 or higher is considered indicative of good reliability. These results demonstrate that measurement of lip-seal strength in adults with this device offers sufficient intra- and inter-investigator reliability.

Change in Autonomic Nervous Activity during Ingestion of Soft Food in Older Nursing Home Residents.

The deterioration in masticatory function often seen in older adults rules out the consumption of hard foods, while a common decline in autonomic nervous response often observed in older adults may result in maladjustment to environmental stresses. The purpose of this study was to investigate whether autonomic nervous activity in older adults increased during the mastication of soft foods compared to at rest. The participants comprised 9 volunteer nursing home residents aged 78 to 100 years. All consumed soft rice as a grain dish and coarsely chopped food as side dishes. The coefficient of variation of R-R intervals (CVRR) and high-frequency (HF) power on electrocardiograph (ECG) served as indices of parasympathetic nervous activity, while the low-frequency (LF)/HF ratio served as an index of sympathetic nervous activity. Total power, reflecting the level of autonomic nervous activity, was also measured. We measured autonomic nervous activity while nursing home residents were eating lunch. HF was 3,457.4±3,037.5 ms2 at rest and 4,085.1±3,697.7 ms2 during mastication. The CVRR was 26.8±16.9% at rest and 26.1±16.1% during mastication. No significant difference was observed in HF or CVRR. On the other hand, the LF/HF ratio was 0.77±0.24 ms2 at rest and 31.0±3.77 ms2 during mastication (p=0.011). A significant difference was observed in the LF/HF ratio between the resting and masticating conditions. Total power was 6,244.1±5,752.5 ms2 at rest and 8,417.7±7,266.4 ms2 during mastication (p=0.038). A significant difference was also observed in total power between resting and masticating conditions. These results suggest that mastication of soft foods stimulates autonomic nervous activity in older adults. In conclusion, autonomic nervous activity increased during chewing soft foods compared to that during the resting level in older adults.

Cell cycle control of spindle pole body duplication and splitting by Sfi1 and Cdc31 in fission yeast.

Spindle pole biogenesis and segregation are tightly coordinated to produce a bipolar mitotic spindle. In yeasts, the spindle pole body (SPB) half-bridge composed of Sfi1 and Cdc31 duplicates to promote the biogenesis of a second SPB. Sfi1 accumulates at the half-bridge in two phases in Schizosaccharomyces pombe, from anaphase to early septation and throughout G2 phase. We found that the function of Sfi1-Cdc31 in SPB duplication is accomplished before septation ends and G2 accumulation starts. Thus, Sfi1 early accumulation at mitotic exit might correspond to half-bridge duplication. We further show that Cdc31 phosphorylation on serine 15 in a Cdk1 (encoded by cdc2) consensus site is required for the dissociation of a significant pool of Sfi1 from the bridge and timely segregation of SPBs at mitotic onset. This suggests that the Cdc31 N-terminus modulates the stability of Sfi1-Cdc31 arrays in fission yeast, and impacts on the timing of establishment of spindle bipolarity.

Effect of chewing or compressing food on autonomic nervous activity in older adults.

OBJECTIVE: To determine if autonomic nervous activity increases in older people during mastication and how this activity is related to the softness of food. We hypothesised that the coefficient of variation of R-R intervals (CVRR), high-frequency (HF) power, low-frequency (LF) power, LF/HF ratio and total power increase during chewing foods within the range of softness from moderate food to extremely soft food in older adults. MATERIALS AND METHODS: Participants were 20 older volunteers (71-90 year old). CVRR and HF on the electrocardiogram (ECG) were used as indices of parasympathetic nervous activity. LF and the LF/HF ratio on the ECG were used as indices of sympathetic nervous activity. Total power, reflecting the level of autonomic nervous activity, was also measured. Participants were asked to chew gum with three different degrees of softness, or to compress extremely soft gum between their palate and tongue. RESULTS: There were significant differences in HF between at resting and all chewing/compressing conditions, but no significant differences relating to food softness. There were significant differences in total power between at resting and all chewing/compressing conditions, but no significant differences relating to food softness. There were no significant differences in LF, LF/HF and CVRR among all conditions. CONCLUSION: Autonomic nervous activity, especially parasympathetic activity in older adults, increased during chewing and compressing food when compared to activity while at rest. Within the range of food's softness from moderate to extreme soft, food's softness had no measurable effect on autonomic nervous activity.

TRIM37 employs peptide motif recognition and substrate-dependent oligomerization to prevent ectopic spindle pole assembly.

Tightly controlled duplication of centrosomes, the major microtubule-organizing centers of animal cells, ensures bipolarity of the mitotic spindle and accurate chromosome segregation. The RBCC (RING-B-box-coiled coil) ubiquitin ligase TRIM37, whose loss is associated with elevated chromosome missegregation and the tumor-prone developmental human disorder Mulibrey nanism, prevents the formation of ectopic spindle poles that assemble around structured condensates containing the centrosomal protein centrobin. Here, we show that TRIM37's TRAF domain, unique in the extended TRIM family, engages peptide motifs in centrobin to suppress condensate formation. TRIM proteins form anti-parallel coiled-coil dimers with RING-B-box domains on each end. Oligomerization due to RING-RING interactions and conformational regulation by B-box-2-B-box-2 interfaces are critical for TRIM37 to suppress centrobin condensate formation. These results indicate that, analogous to anti-viral TRIM ligases, TRIM37 activation is linked to the detection of oligomerized substrates. Thus, TRIM37 couples peptide motif recognition and substrate-dependent oligomerization to effect ubiquitination-mediated clearance of ectopic centrosomal protein assemblies.

BUB-1-bound PLK-1 directs CDC-20 kinetochore recruitment to ensure timely embryonic mitoses.

During mitosis, chromosomes assemble kinetochores to dynamically couple with spindle microtubules.1,2 Kinetochores also function as signaling hubs directing mitotic progression by recruiting and controlling the fate of the anaphase promoting complex/cyclosome (APC/C) activator CDC-20.3,4,5 Kinetochores either incorporate CDC-20 into checkpoint complexes that inhibit the APC/C or dephosphorylate CDC-20, which allows it to interact with and activate the APC/C.4,6 The importance of these two CDC-20 fates likely depends on the biological context. In human somatic cells, the major mechanism controlling mitotic progression is the spindle checkpoint. By contrast, progression through mitosis during the cell cycles of early embryos is largely checkpoint independent.7,8,9,10 Here, we first show that CDC-20 phosphoregulation controls mitotic duration in the C. elegans embryo and defines a checkpoint-independent temporal mitotic optimum for robust embryogenesis. CDC-20 phosphoregulation occurs at kinetochores and in the cytosol. At kinetochores, the flux of CDC-20 for local dephosphorylation requires an ABBA motif on BUB-1 that directly interfaces with the structured WD40 domain of CDC-20.6,11,12,13 We next show that a conserved "STP" motif in BUB-1 that docks the mitotic kinase PLK-114 is necessary for CDC-20 kinetochore recruitment and timely mitotic progression. The kinase activity of PLK-1 is required for CDC-20 to localize to kinetochores and phosphorylates the CDC-20-binding ABBA motif of BUB-1 to promote BUB-1-CDC-20 interaction and mitotic progression. Thus, the BUB-1-bound pool of PLK-1 ensures timely mitosis during embryonic cell cycles by promoting CDC-20 recruitment to the vicinity of kinetochore-localized phosphatase activity.

Oral function is associated with the body and muscle mass indices of middle-aged dental patients.

OBJECTIVES: Undernutrition is associated with frailty, one of the common reasons for seeking long-term care. In older adults, nutritional status is known to be associated with oral function; however, it is not yet known if there is a similar association in middle-aged adults. The present study determined the association between nutritional status and oral function in middle-aged adults. MATERIAL AND METHODS: This cross-sectional study was conducted in 117 outpatients aged 40-64 years who underwent dental check-up at a private dental clinic. Factors associated with oral function, including oral moisture, number of teeth present, oral diadochokinesis, tongue pressure, lip-seal strength, and masticatory performance, were evaluated. Body mass index (BMI), fat-free mass index (FFMI), and skeletal muscle mass index (SMI) were analyzed as nutritional statuses. Pearson's correlation analysis was conducted to determine the correlation between nutritional statuses and other variables. Multiple linear regression analysis was performed, with adjustment for age and sex, using BMI, FFMI, or SMI as response variables and oral moisture, maximum tongue pressure, lip-seal strength, oral diadochokinetic rate, and masticatory performance as explanatory variables. RESULTS: All nutritional statuses showed significant correlation with maximum tongue pressure and lip-seal strength. Multiple linear regression analysis revealed that BMI was associated with maximum tongue pressure and lip-seal strength, whereas FFMI and SMI showed significant association with sex, maximum tongue pressure, and lip-seal strength. CONCLUSIONS: In middle-aged outpatients at a regional dental clinic, lip-seal strength and tongue pressure were positively associated with BMI, FFMI, and SMI.

Distribution of lip-seal strength and its relation to oral motor functions.

OBJECTIVES: Lip-seal strength, which represents the muscle strength of the lips, appears to chiefly contribute to mastication and pronunciation. However, the functional characteristics of lip-seal strength in adults are still undefined. The present study aimed to understand not only the distribution of lip-seal strength in adult men and women but also the effect of age on this strength and identify oral motor functions correlated with lip-seal strength. MATERIALS AND METHODS: The subjects included 339 participants (men: 170, age 39.2 ± 18.2 years; women: 169, age 43.1 ± 19.7 years). Oral motor function was evaluated for lip-seal strength, oral diadochokinesis (ODK), tongue pressure, occlusal force, and masticatory performance. Statistical analyses included the Shapiro-Wilk, Mann-Whitney U, and Jonckheere-Terpstra tests, in addition to the Spearman's correlation analysis and curvilinear regression analysis. RESULTS: Lip-seal strength did not have a normal distribution (p < 0.001). The mean ± standard deviation and median (first quartile, third quartile) of lip-seal strength were 11.2 ± 3.4 and 10.9 (8.7, 13.2)N for the whole sample, 12.3 ± 3.4 and 11.9 (9.4, 14.4)N for men, and 10.2 ± 3.0 and 9.9 (8.0, 12.0)N for women. A significant difference was observed in lip-seal strength between men and women (p < 0.001). Oral motor functions showed a marked correlation with lip-seal strength, including tongue pressure, occlusal force, and masticatory performance and ODK (/pa/ and /ta/), tongue pressure, and masticatory ability in men and women, respectively. In women, lip-seal strength declined with increase in age. CONCLUSIONS: Lip-seal strength was non-normally distributed in both men and women, and lip-seal strength was affected by age only in women. Lip-seal strength and multiple oral motor functions were significantly correlated. Because the indicators of perioral muscle strength and performance were correlated with lip-seal strength, lip-seal strength may also partially reflect the condition of the perioral muscles.

TRIM37 prevents formation of condensate-organized ectopic spindle poles to ensure mitotic fidelity.

Centrosomes are composed of a centriolar core surrounded by pericentriolar material that nucleates microtubules. The ubiquitin ligase TRIM37 localizes to centrosomes, but its centrosomal roles are not yet defined. We show that TRIM37 does not control centriole duplication, structure, or the ability of centrioles to form cilia but instead prevents assembly of an ectopic centrobin-scaffolded structured condensate that forms by budding off of centrosomes. In ∼25% of TRIM37-deficient cells, the condensate organizes an ectopic spindle pole, recruiting other centrosomal proteins and acquiring microtubule nucleation capacity during mitotic entry. Ectopic spindle pole-associated transient multipolarity and multipolar segregation in TRIM37-deficient cells are suppressed by removing centrobin, which interacts with and is ubiquitinated by TRIM37. Thus, TRIM37 ensures accurate chromosome segregation by preventing the formation of centrobin-scaffolded condensates that organize ectopic spindle poles. Mutations in TRIM37 cause the disorder mulibrey nanism, and patient-derived cells harbor centrobin condensate-organized ectopic poles, leading us to propose that chromosome missegregation is a pathological mechanism in this disorder.

Polo-like kinase 1 independently controls microtubule-nucleating capacity and size of the centrosome.

Centrosomes are composed of a centriolar core surrounded by a pericentriolar material (PCM) matrix that docks microtubule-nucleating γ-tubulin complexes. During mitotic entry, the PCM matrix increases in size and nucleating capacity in a process called centrosome maturation. Polo-like kinase 1 (PLK1) is recruited to centrosomes and phosphorylates PCM matrix proteins to drive their self-assembly, which leads to PCM expansion. Here, we show that in addition to controlling PCM expansion, PLK1 independently controls the generation of binding sites for γ-tubulin complexes on the PCM matrix. Selectively preventing the generation of PLK1-dependent γ-tubulin docking sites led to spindle defects and impaired chromosome segregation without affecting PCM expansion, highlighting the importance of phospho-regulated centrosomal γ-tubulin docking sites in spindle assembly. Inhibiting both γ-tubulin docking and PCM expansion by mutating substrate target sites recapitulated the effects of loss of centrosomal PLK1 on the ability of centrosomes to catalyze spindle assembly.

Bimodal Binding of STIL to Plk4 Controls Proper Centriole Copy Number.

The number of centrioles is tightly controlled to ensure bipolar spindle assembly, which is a prerequisite to maintain genome integrity. However, our understanding of the fundamental principle that governs the formation of a single procentriole per parental centriole is incomplete. Here, we show that the local restriction of Plk4, a master regulator of the procentriole formation, is achieved by a bimodal interaction of STIL with Plk4. We demonstrate that the conserved short coiled-coil region of STIL binds to and protects Plk4 from protein degradation at the site of procentriole formation. On the other hand, the conserved C-terminal region of STIL named truncated in microcephaly (TIM) domain promotes autophosphorylation and degradation of adjacent Plk4 by the direct interaction. Thus, we propose that positive and negative regulation based on the bimodal binding of Plk4 and STIL ensures the formation of a single procentriole per parental centriole.