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1.
Am J Orthod Dentofacial Orthop ; 162(3): 410-428, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35701285

ABSTRACT

This report aimed to describe the long-term effects of craniofacial growth modification treatment on sleep and breathing functions in a 7-year-old girl diagnosed with skeletal Class III malocclusion and sleep-disordered breathing. Based on the flowchart of orthodontic intervention protocol that we proposed for phenotype-based patient selection and skeletal target-based treatment selection for pediatric patients with sleep-disordered breathing, a 2-phase treatment targeting the nasomaxillary complex was performed. Posttreatment 3-dimensional changes in the skeletal structure and upper airway were evaluated in association with functional assessment using a validated pediatric sleep questionnaire and home sleep test. Esthetic improvement and obstructive sleep apnea cure were achieved without skeletal surgery. The 2-year retention records showed stable occlusion and improved facial profile with normal breathing and sleep.


Subject(s)
Malocclusion, Angle Class III , Malocclusion , Sleep Apnea Syndromes , Sleep Apnea, Obstructive , Clinical Protocols , Follow-Up Studies , Humans , Malocclusion/therapy , Malocclusion, Angle Class III/therapy , Sleep Apnea, Obstructive/surgery , Sleep Apnea, Obstructive/therapy
2.
Eur J Orthod ; 44(1): 66-77, 2022 01 25.
Article in English | MEDLINE | ID: mdl-34379120

ABSTRACT

OBJECTIVES: The aim of the study was to evaluate the accuracy of a cascaded two-stage convolutional neural network (CNN) model in detecting upper airway (UA) soft tissue landmarks in comparison with the skeletal landmarks on the lateral cephalometric images. MATERIALS AND METHODS: The dataset contained 600 lateral cephalograms of adult orthodontic patients, and the ground-truth positions of 16 landmarks (7 skeletal and 9 UA landmarks) were obtained from 500 learning dataset. We trained a UNet with EfficientNetB0 model through the region of interest-centred circular segmentation labelling process. Mean distance errors (MDEs, mm) of the CNN algorithm was compared with those from human examiners. Successful detection rates (SDRs, per cent) assessed within 1-4 mm precision ranges were compared between skeletal and UA landmarks. RESULTS: The proposed model achieved MDEs of 0.80 ± 0.55 mm for skeletal landmarks and 1.78 ± 1.21 mm for UA landmarks. The mean SDRs for UA landmarks were 72.22 per cent for 2 mm range, and 92.78 per cent for 4 mm range, contrasted with those for skeletal landmarks amounting to 93.43 and 98.71 per cent, respectively. As compared with mean interexaminer difference, however, this model showed higher detection accuracies for geometrically constructed UA landmarks on the nasopharynx (AD2 and Ss), while lower accuracies for anatomically located UA landmarks on the tongue (Td) and soft palate (Sb and St). CONCLUSION: The proposed CNN model suggests the availability of an automated cephalometric UA assessment to be integrated with dentoskeletal and facial analysis.


Subject(s)
Face , Neural Networks, Computer , Adult , Algorithms , Cephalometry , Humans , Palate, Soft/diagnostic imaging
3.
Europace ; 19(suppl_4): iv1-iv9, 2017 Dec 01.
Article in English | MEDLINE | ID: mdl-29220421

ABSTRACT

AIMS: We aim to determine the optimal dose of dabigatran in Korean patients with atrial fibrillation (AF). METHODS AND RESULTS: We analysed 1834 patients with non-valvular AF, classified into a warfarin group (n = 990), dabigatran 150 mg group (D150, n = 294), and 110 mg group (D110, n = 550). The D110 group was further classified into patients concordant (co-D110, n = 367) and patients discordant (di-D110, n = 183) with guidelines to dose reduction. Propensity-matched 1-year clinical outcomes were then compared. Efficacy outcomes were defined as thromboembolism composed of new-onset stroke or systemic embolism. Safety outcomes were major bleeding. Both D150 and D110 had comparable efficacies as warfarin. However, only D110 significantly lowered the risk of major bleeding [hazard ratio (HR) 0.19, 95% confidence interval (CI) 0.07-0.55, P = 0.002]. In a subgroup analysis according to guideline-concordant indications for dose reduction, both co-D110 and di-D110 displayed a comparable efficacy as warfarin. Both co-D110 (HR 0.22, 95% CI 0.06-0.76, P = 0.017) and di-D110 (HR 0.11, 95% CI 0.02-0.81, P = 0.030) significantly lowered incidences of major bleeding. There were no differences in the efficacy and safety between di-D110 and D150, and net clinical outcomes were similar. CONCLUSION: Although D150 and D110 had a comparable efficacy, only D110 lowered the risk of major bleeding in Korean AF patients compared with warfarin. Even the guideline-discordant use of dabigatran 110 mg demonstrated a similar efficacy and safety compared with D150. However, further prospective randomized trials are needed in order to comprehensively evaluate whether D150 or D110 is the optimal dosage in Asian patients with AF.


Subject(s)
Anticoagulants/administration & dosage , Antithrombins/administration & dosage , Atrial Fibrillation/drug therapy , Blood Coagulation/drug effects , Dabigatran/administration & dosage , Hemorrhage/prevention & control , Stroke/prevention & control , Thromboembolism/prevention & control , Warfarin/administration & dosage , Aged , Aged, 80 and over , Anticoagulants/adverse effects , Antithrombins/adverse effects , Atrial Fibrillation/blood , Atrial Fibrillation/complications , Atrial Fibrillation/diagnosis , Chi-Square Distribution , Dabigatran/adverse effects , Female , Hemorrhage/chemically induced , Humans , Kaplan-Meier Estimate , Logistic Models , Male , Middle Aged , Propensity Score , Proportional Hazards Models , Republic of Korea , Retrospective Studies , Risk Assessment , Risk Factors , Stroke/blood , Stroke/diagnosis , Stroke/etiology , Thromboembolism/blood , Thromboembolism/diagnosis , Thromboembolism/etiology , Time Factors , Treatment Outcome , Warfarin/adverse effects
4.
BMC Musculoskelet Disord ; 16: 141, 2015 Jun 10.
Article in English | MEDLINE | ID: mdl-26059549

ABSTRACT

BACKGROUND: A localized non-surgical delivery of allogeneic human chondrocytes (hChonJ) with irradiated genetically modified chondrocytes (hChonJb#7) expressing transforming growth factor-ß1 (TGF-ß1) showed efficacy in regenerating cartilage tissue in our pre-clinical studies and human Phase I and II clinical trials. These previous observations led us to investigate the molecular mechanisms of the cartilage regeneration. METHODS: Genetically modified TGF-ß1preprotein was evaluated by monitoring cell proliferation inhibition activity. The effect of modified TGF-ß1 on chondrocytes was evaluated based on the type II collagen mRNA levels and the amount of glycosaminoclycan (GAG) formed around chondrocytes, which are indicative markers of redifferentiated chondrocytes. Among the cartilage matrix components produced by hChonJb#7 cells, type II collagen and proteoglycan, in addition to TGF-ß1, were also tested to see if they could induce hChonJ redifferentiation. The ability of chondrocytes to attach to artificially induced defects in rabbit cartilage was tested using fluorescent markers. RESULTS: Throughout these experiments, the TGF-ß1 produced from hChonJb#7 was shown to be equally as active as the recombinant human TGF-ß1. Type II collagen and GAG production were induced in hChonJ cells by TGF-ß1 secreted from the irradiated hChonJb#7 cells when the cells were co-cultured in micro-masses. Both hChonJ and hChonJb#7 cells could attach efficiently to the defect area in the rabbit cartilage. CONCLUSIONS: This study suggests that the mixture (TG-C) of allogeneic human chondrocytes (hChonJ) and irradiated genetically modified human chondrocytes expressing TGF-ß1 (hChonJb#7) attach to the damaged cartilage area to produce type II collagen-GAG matrices by providing a continuous supply of active TGF-ß1.


Subject(s)
Chondrocytes/pathology , Chondrogenesis , Collagen Type II/metabolism , Glycosaminoglycans/metabolism , Transforming Growth Factor beta1/metabolism , Animals , COS Cells , Cartilage Diseases/metabolism , Cartilage Diseases/pathology , Cartilage Diseases/therapy , Cartilage, Articular/metabolism , Cartilage, Articular/pathology , Cartilage, Articular/surgery , Cell Adhesion , Chlorocebus aethiops , Chondrocytes/drug effects , Chondrocytes/transplantation , Chondrogenesis/drug effects , Coculture Techniques , Disease Models, Animal , Femur/metabolism , Femur/pathology , Femur/surgery , Genetic Therapy/methods , Hep G2 Cells , Humans , Infant , Mutation , Rabbits , Regeneration , Transfection , Transforming Growth Factor beta1/genetics , Transforming Growth Factor beta1/pharmacology , Up-Regulation
5.
Biochem Biophys Res Commun ; 443(1): 259-65, 2014 Jan 03.
Article in English | MEDLINE | ID: mdl-24309115

ABSTRACT

Covalent conjugation of proteins with small ubiquitin-like modifier 1 (SUMO-1) plays a critical role in a variety of cellular functions including cell cycle control, replication, and transcriptional regulation. Nuclear mitotic apparatus protein (NuMA) localizes to spindle poles during mitosis, and is an essential component in the formation and maintenance of mitotic spindle poles. Here we show that NuMA is a target for covalent conjugation to SUMO-1. We find that the lysine 1766 residue is the primary NuMA acceptor site for SUMO-1 conjugation. Interestingly, SUMO modification of endogenous NuMA occurs at the entry into mitosis and this modification is reversed after exiting from mitosis. Knockdown of Ubc9 or forced expression of SENP1 results in impairment of the localization of NuMA to mitotic spindle poles during mitosis. The SUMOylation-deficient NuMA mutant is defective in microtubule bundling, and multiple spindles are induced during mitosis. The mitosis-dependent dynamic SUMO-1 modification of NuMA might contribute to NuMA-mediated formation and maintenance of mitotic spindle poles during mitosis.


Subject(s)
Antigens, Nuclear/metabolism , Cell Cycle/physiology , Nuclear Matrix-Associated Proteins/metabolism , SUMO-1 Protein/metabolism , Sumoylation , Antigens, Nuclear/genetics , Cell Cycle/genetics , Cell Cycle Proteins , Cysteine Endopeptidases , Endopeptidases/genetics , Endopeptidases/metabolism , HeLa Cells , Humans , Microtubules/metabolism , Mitosis/genetics , Mitosis/physiology , Mutagenesis, Site-Directed , Nuclear Matrix-Associated Proteins/genetics , Spindle Apparatus/metabolism , Two-Hybrid System Techniques
6.
J Korean Med Sci ; 29(4): 527-35, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24753700

ABSTRACT

We compared clinical characteristics, management, and clinical outcomes of nonagenarian acute myocardial infarction (AMI) patients (n=270, 92.3 ± 2.3 yr old) with octogenarian AMI patients (n=2,145, 83.5 ± 2.7 yr old) enrolled in Korean AMI Registry (KAMIR). Nonagenarians were less likely to have hypertension, diabetes and less likely to be prescribed with beta-blockers, statins, and glycoprotein IIb/IIIa inhibitors compared with octogenarians. Although percutaneous coronary intervention (PCI) was preferred in octogenarians than nonagenarians, the success rate of PCI between the two groups was comparable. In-hospital mortality, the composite of in-hospital adverse outcomes and one year mortality were higher in nonagenarians than in octogenarians. However, the composite of the one year major adverse cardiac events (MACEs) was comparable between the two groups without differences in MI or re-PCI rate. PCI improved 1-yr mortality (adjusted hazard ratio [HR], 0.50; 95% confidence interval [CI], 0.36-0.69, P<0.001) and MACEs (adjusted HR, 0.47; 95% CI, 0.37-0.61, P<0.001) without significant complications both in nonagenarians and octogenarians. In conclusion, nonagenarians had similar 1-yr MACEs rates despite of higher in-hospital and 1-yr mortality compared with octogenarian AMI patients. PCI in nonagenarian AMI patients was associated to better 1-yr clinical outcomes.


Subject(s)
Angioplasty, Balloon, Coronary , Myocardial Infarction/diagnosis , Percutaneous Coronary Intervention , Acute Disease , Age Factors , Aged, 80 and over , Electrocardiography , Female , Hospital Mortality , Humans , Male , Myocardial Infarction/mortality , Myocardial Infarction/therapy , Proportional Hazards Models , Registries , Treatment Outcome
7.
Am J Orthod Dentofacial Orthop ; 144(1): 23-31, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23810042

ABSTRACT

INTRODUCTION: The aim of the study was to elucidate whether a newly developed, minimally invasive procedure, piezopuncture, would be a logical modification for accelerating tooth movement in the maxilla and the mandible. METHODS: Ten beagle dogs were divided into 2 groups. Traditional orthodontic tooth movement was performed in the control group. In the experimental group, a piezotome was used to make cortical punctures penetrating the gingiva around the moving tooth. Measurements were made in weeks 1 through 6. Tooth movement and bone apposition rates from the histomorphometric analyses were evaluated by independent t tests. RESULTS: The cumulative tooth movement distance was greater in the piezopuncture group than in the control group: 3.26-fold in the maxilla and 2.45-fold in the mandible. Piezopuncture significantly accelerated the tooth movements at all observation times, and the acceleration was greatest during the first 2 weeks for the maxilla and the second week for the mandible. Anabolic activity was also increased by piezopuncture: 2.55-fold in the maxilla and 2.35-fold in the mandible. CONCLUSIONS: Based on the different effects of piezopuncture on the maxilla and the mandible, the results of a clinical trial of piezopuncture with optimized protocols might give orthodontists a therapeutic benefit for reducing treatment duration.


Subject(s)
Bone Remodeling/physiology , Piezosurgery/methods , Punctures/methods , Tooth Movement Techniques/methods , Alveolar Process/pathology , Alveolar Process/surgery , Animals , Anthraquinones , Bicuspid/pathology , Biomechanical Phenomena , Cuspid/pathology , Dogs , Fluoresceins , Fluorescent Dyes , Gingiva/surgery , Male , Mandible/metabolism , Mandible/surgery , Maxilla/metabolism , Maxilla/surgery , Minimally Invasive Surgical Procedures , Molar, Third/pathology , Orthodontic Anchorage Procedures/instrumentation , Orthodontic Anchorage Procedures/methods , Osteoclasts/pathology , Osteogenesis/physiology , Periodontal Ligament/pathology , Periodontal Ligament/surgery , Piezosurgery/instrumentation , Punctures/instrumentation , Random Allocation , Time Factors
8.
Korean J Orthod ; 51(3): 166-178, 2021 May 25.
Article in English | MEDLINE | ID: mdl-33984224

ABSTRACT

OBJECTIVE: To investigate dimensional changes in regional pharyngeal airway spaces after premolar extraction in bimaxillary skeletal protrusion (BSP) patients according to vertical skeletal pattern, and to further identify dentoskeletal risk factors to predict posttreatment pharyngeal changes. METHODS: Fifty-five adults showing BSP treated with microimplant anchorage after four premolar extractions were included in this retrospective study. The subjects were divided into two groups according to the mandibular plane steepness: hyperdivergent (Frankfort horizontal plane to mandibular plane [FH-MP] ≥ 30) and nonhyperdivergent groups (FH-MP < 30). The control group consisted of 20 untreated adults with skeletal Class I normodivergent pattern and favorable profile. Treatment changes in cephalometric variables were evaluated and compared. The association between posttreatment changes in the dentoskeletal and upper airway variables were analyzed using linear regression analysis. RESULTS: The BSP patients showed no significant decrease in the pharyngeal dimensions to the lower level in comparison with controls, except for middle airway space (MAS, p < 0.01). The upper airway variable representing greater decrease in the hyperdivergent group than in the nonhyperdivergent group was the MAS (p < 0.01). Posttreatment changes in FH-MP had negative correlation with changes in MAS (ß = -0.42, p < 0.01) and inferior airway space (ß = -0.52, p < 0.01) as a result of multivariable regression analysis adjusted for sagittal skeletal relationship. CONCLUSIONS: Decreased pharyngeal dimensions after treatment in BSP patients showed no significant difference from the normal range of pharyngeal dimensions. However, the glossopharyngeal airway space may be susceptible to treatment when vertical dimension increased in hyperdivergent BSP patients.

9.
Curr Biol ; 12(23): 2048-54, 2002 Dec 10.
Article in English | MEDLINE | ID: mdl-12477395

ABSTRACT

The anaphase-promoting complex (APC) is a conserved multisubunit ubiquitin ligase required for the degradation of key cell cycle regulators. Components of the APC have been identified through genetic screens in both Schizosaccharomyces pombe and Saccharomyces cerevisiae as well as through biochemical purification coupled with mass spectrometric protein identification. With these approaches, 11 subunits of the core S. cerevisiae APC have been identified. Here, we have applied a tandem affinity purification approach coupled with direct analysis of the purified complexes by mass spectrometry (DALPC) to reveal additional subunits of both the S. pombe and S. cerevisiae APCs. Our data increase the total number of identified APC subunits to 13 in both yeasts and indicate that previous approaches were biased against the identification of small subunits. These results underscore the power of direct analysis of protein complexes by mass spectrometry and set the foundation for further functional and structural studies of the APC.


Subject(s)
Ligases/genetics , Proteome , Schizosaccharomyces pombe Proteins/genetics , Schizosaccharomyces/genetics , Ubiquitin-Protein Ligase Complexes , Anaphase , Anaphase-Promoting Complex-Cyclosome , Ligases/isolation & purification , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/isolation & purification , Schizosaccharomyces/cytology , Schizosaccharomyces pombe Proteins/isolation & purification
10.
Korean J Food Sci Anim Resour ; 36(3): 412-20, 2016.
Article in English | MEDLINE | ID: mdl-27433113

ABSTRACT

The objective of this study was to investigate characteristics and functionality of yogurt applied red ginseng extract. Yogurts added with red ginseng extract (0.5, 1, 1.5, and 2%) were produced using Lactobacillus acidophilus and Streptococcus thermophilus and stored at refrigerated temperature. During fermentation, pH was decreased whereas titratable aicidity and viable cell counts of L. acidophilus and S. thermophilus were increased. The composition of yogurt samples was measured on day 1, an increase of red ginseng extract content in yogurt resulted in an increase in lactose, protein, total solids, and ash content, whereas fat and moisture content decreased. The pH value and cell counts of L. acidophilus and S. thermophilus were declined, however titratable acidity was increased during storage period. The antioxidant capacity was measured as diverse methods. During refrigerated storage time, the value of antioxidant effect was decreased, however, yogurt fortified with red ginseng extract had higher capacity than plain yogurt. The antioxidant effect was improved in proportion to concentration of red ginseng extract. These data suggests that red ginseng extract could affect to reduce fermentation time of yogurt and enhance antioxidant capacity.

11.
Am J Cardiol ; 115(1): 1-7, 2015 Jan 01.
Article in English | MEDLINE | ID: mdl-25456863

ABSTRACT

Many patients discontinue statin after acute myocardial infarction (AMI) despite its necessity. However, limited data are available describing the clinical impact of statin withdrawal after AMI. This study enrolled 3,807 patients in the Korean multicenter registry who survived for 1 year after AMI. All patients were prescribed statin at discharge and were divided into 2 groups on the basis of statin withdrawal history; 603 patients had a history of statin discontinuation and 3,204 patients continued statin therapy. The primary outcome was mortality from any cause. We also analyzed the incidence of cardiac death, nonfatal myocardial infarction, any revascularization, and stroke. The duration of follow-up was 4 years after AMI. Statin withdrawal was associated with higher mortality than continued statin treatment (hazard ratio 3.45, 95% confidence interval 2.81 to 4.24, p <0.001), primarily as the result of increased cardiac mortality (hazard ratio 4.65, 95% confidence interval 3.14 to 6.87, p <0.001). However, the incidences of nonfatal myocardial infarction, any revascularization, and stroke were not different between the groups. Analysis by propensity score matching did not affect the results. In conclusion, many patients experienced statin withdrawal after AMI, which significantly increased long-term mortality in the present study. Careful education and monitoring are needed to reduce adverse cardiac outcomes in patients after AMI.


Subject(s)
Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Myocardial Infarction/drug therapy , Patient Discharge , Registries , Withholding Treatment/trends , Electrocardiography , Female , Follow-Up Studies , Humans , Male , Middle Aged , Myocardial Infarction/mortality , Propensity Score , Prospective Studies , Republic of Korea/epidemiology , Risk Factors , Survival Rate/trends , Time Factors , Treatment Outcome
12.
BMC Cancer ; 4: 70, 2004 Sep 30.
Article in English | MEDLINE | ID: mdl-15456519

ABSTRACT

BACKGROUND: SV40 DNA replication system is a very useful tool to understand the mechanism of replication, which is a tightly regulated process. Many environmental and cellular factors can induce cell cycle arrest or apoptosis by inhibiting DNA replication. In the course of our search for bioactive metabolites from the marine sponges, psammaplin A was found to have some anticancer properties, the possible mechanism of which was studied. METHODS: Cell viability was determined by Cell Counting Kit-8 (CCK-8) to count living RAW264.7 cells by combining 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium (WST-8) and 1-methoxy-phenazine methosulfate (1-methoxy-PMS). The effect of psammaplin A on DNA replication was carried out in SV40 DNA replication system in vitro. The activities of topoisomerase I and polymerase alpha-primase were measured by the relaxation of superhelical plasmid DNA and the incorporation of [3H]dTTP to the template respectively. The ssDNA binding activity of RPA was assessed by Gel Mobility Shift Assay (GMSA). RESULTS: We have found that psammaplin A delivers significant cytotoxic activity against the RAW264.7 cell line. It was also found that psammaplin A could substantially inhibit SV40 DNA replication in vitro, in which polymerase alpha-primase is one of its main targets. CONCLUSION: Taken together, we suggest that psammaplin A-induced cytotoxicity may correlate with its inhibition on DNA replication. Psammaplin A has the potential to be developed as an anticancer drug.


Subject(s)
DNA Polymerase I/antagonists & inhibitors , DNA Primase/antagonists & inhibitors , DNA Replication/drug effects , Disulfides/pharmacology , Porifera/chemistry , Topoisomerase II Inhibitors , Tyrosine/analogs & derivatives , Tyrosine/pharmacology , Animals , Cell Line, Tumor , Cell Survival/drug effects , Drug Screening Assays, Antitumor , Simian virus 40/drug effects , Simian virus 40/physiology , Virus Replication/drug effects , Virus Replication/genetics
14.
Mol Cell ; 28(5): 871-85, 2007 Dec 14.
Article in English | MEDLINE | ID: mdl-18082611

ABSTRACT

The anaphase-promoting complex/cyclosome (APC/C) is a conserved multisubunit E3 ubiquitin (Ub) ligase required to signal the degradation of key cell-cycle regulators. Using single particle cryo-electron microscopy (cryo-EM), we have determined a three-dimensional (3D) structure of the core APC/C from Schizosaccharomyces pombe bound to the APC/C activator Slp1/Cdc20. At the 27 A resolution of our density map, the APC/C is a triangular-shaped structure, approximately 19x17x15 nm in size, with a deep internal cavity and a prominent horn-like protrusion emanating from a lip of the cavity. Using antibody labeling and mutant analysis, we have localized 12 of 13 core APC/C components, as well as the position of the activator Slp1, enabling us to propose a structural model of APC/C organization. Comparison of the APC/C with another multiprotein E3 ligase, the SCF complex, uncovers remarkable structural similarities.


Subject(s)
Cell Cycle Proteins/metabolism , Schizosaccharomyces pombe Proteins/metabolism , Schizosaccharomyces/metabolism , Ubiquitin-Protein Ligase Complexes/chemistry , Ubiquitin-Protein Ligase Complexes/metabolism , Anaphase-Promoting Complex-Cyclosome , Cdc20 Proteins , Cell Cycle Proteins/chemistry , Chromatography, Affinity , Cryoelectron Microscopy , Immunoblotting , Mitosis/physiology , Models, Molecular , Mutagenesis, Site-Directed , Mutation , Protein Conformation , Schizosaccharomyces/genetics , Schizosaccharomyces/growth & development , Schizosaccharomyces pombe Proteins/chemistry , Ubiquitin-Protein Ligase Complexes/isolation & purification , Ubiquitin-Protein Ligases/chemistry , Ubiquitin-Protein Ligases/isolation & purification , Ubiquitin-Protein Ligases/metabolism , Ubiquitination
15.
J Biol Chem ; 281(43): 32284-93, 2006 Oct 27.
Article in English | MEDLINE | ID: mdl-16950791

ABSTRACT

The anaphase-promoting complex/cyclosome (APC/C) is a conserved multisubunit ubiquitin ligase required for the degradation of key cell cycle regulators. The APC/C becomes active at the metaphase/anaphase transition and remains active during G(1) phase. One mechanism linked to activation of the APC/C is phosphorylation. Although many sites of mitotic phosphorylation have been identified in core components of the APC/C, the consequence of any individual phosphorylation event has not been elucidated in vivo. In this study, we show that Hcn1 is an essential core component of the fission yeast APC/C and is critical for maintaining complex integrity. Moreover, Hcn1 is a phosphoprotein in vivo. Phosphorylation of Hcn1 occurs at a single Cdk1 site in vitro and in vivo. Mutation of this site to alanine, but not aspartic acid, compromises APC/C function and leads to a specific defect in the completion of cell division.


Subject(s)
Fungal Proteins/metabolism , Repressor Proteins/metabolism , Schizosaccharomyces pombe Proteins/metabolism , Schizosaccharomyces/metabolism , Ubiquitin-Protein Ligase Complexes/physiology , Alanine/metabolism , Amino Acid Substitution , Anaphase-Promoting Complex-Cyclosome , Cell Cycle Proteins/genetics , Fungal Proteins/chemistry , Fungal Proteins/genetics , G2 Phase , Gene Deletion , Green Fluorescent Proteins/metabolism , Phosphorylation , Repressor Proteins/chemistry , Repressor Proteins/genetics , Schizosaccharomyces/cytology , Schizosaccharomyces/genetics , Schizosaccharomyces pombe Proteins/chemistry , Schizosaccharomyces pombe Proteins/genetics
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