15 results on '"Chabu C"'
Search Results
2. Malaria community case management usage and quality of malaria care in a moderate Plasmodium falciparum burden region of Chadiza District, Zambia.
- Author
-
Wallender E, Kabamba B, Rutagwera MI, Kangale C, Miller JM, Porter T, Musunse M, Gallalee S, Bennett A, Psychas P, Gutman JR, Hamainza B, and Thwing J
- Subjects
- Zambia epidemiology, Humans, Child, Preschool, Adolescent, Child, Male, Infant, Female, Adult, Young Adult, Middle Aged, Infant, Newborn, Aged, Prevalence, Quality of Health Care statistics & numerical data, Diagnostic Tests, Routine statistics & numerical data, Case Management statistics & numerical data, Malaria, Falciparum epidemiology
- Abstract
Background: Malaria community case management (CCM) can improve timely access to healthcare, and CCM programmes in sub-Saharan Africa are expanding from serving children under 5 years (CU5) only to all ages. This report characterizes malaria case management in the setting of an age-expanded CCM programme in Chadiza District, Zambia., Methods: Thirty-three households in each of 73 eligible communities were randomly selected to participate in a household survey preceding a trial of proactive CCM (NCT04839900). All household members were asked about fever in the prior two weeks and received a malaria rapid diagnostic test (RDT); those reporting fever were asked about healthcare received. Weighted population estimates were calculated and mixed effects regression was used to assess factors associated with malaria care seeking., Results: Among 11,030 (98.6%) participants with RDT results (2,357 households), parasite prevalence was 19.1% by RDT; school-aged children (SAC, 5-14 years) had the highest prevalence (28.8%). Prior fever was reported by 12.4% of CU5, 7.5% of SAC, and 7.2% of individuals ≥ 15 years. Among those with prior fever, 34.0% of CU5, 56.0% of SAC, and 22.6% of individuals ≥ 15 years had a positive survey RDT and 73.7% of CU5, 66.5% of SAC, and 56.3% of individuals ≥ 15 years reported seeking treatment; 76.7% across all ages visited a CHW as part of care. Nearly 90% (87.8%) of people who visited a CHW reported a blood test compared with 73.5% seen only at a health facility and/or pharmacy (p < 0.001). Reported malaria treatment was similar by provider, and 85.9% of those with a reported positive malaria test reported getting malaria treatment; 66.9% of the subset with prior fever and a positive survey RDT reported malaria treatment. Age under 5 years, monthly or more frequent CHW home visits, and greater wealth were associated with increased odds of receiving healthcare., Conclusions: Chadiza District had high CHW coverage among individuals who sought care for fever. Further interventions are needed to increase the proportion of febrile individuals who receive healthcare. Strategies to decrease barriers to healthcare, such as CHW home visits, particularly targeting those of all ages in lower wealth strata, could maximize the benefits of CHW programmes., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)
- Published
- 2024
- Full Text
- View/download PDF
3. Trends in SARS-CoV-2 seroprevalence among pregnant women attending first antenatal care visits in Zambia: A repeated cross-sectional survey, 2021-2022.
- Author
-
Heilmann E, Tembo T, Fwoloshi S, Kabamba B, Chilambe F, Kalenga K, Siwingwa M, Mulube C, Seffren V, Bolton-Moore C, Simwanza J, Yingst S, Yadav R, Rogier E, Auld AF, Agolory S, Kapina M, Gutman JR, Savory T, Kangale C, Mulenga LB, Sikazwe I, and Hines JZ
- Abstract
SARS-CoV-2 serosurveys help estimate the extent of transmission and guide the allocation of COVID-19 vaccines. We measured SARS-CoV-2 seroprevalence among women attending ANC clinics to assess exposure trends over time in Zambia. We conducted repeated cross-sectional SARS-CoV-2 seroprevalence surveys among pregnant women aged 15-49 years attending their first ANC visits in four districts of Zambia (two urban and two rural) during September 2021-September 2022. Serologic testing was done using a multiplex bead assay which detects IgG antibodies to the nucleocapsid protein and the spike protein receptor-binding domain (RBD). We calculated monthly SARS-CoV-2 seroprevalence by district. We also categorized seropositive results as infection alone, infection and vaccination, or vaccination alone based on anti-RBD and anti-nucleocapsid test results and self-reported COVID-19 vaccination status (vaccinated was having received ≥1 dose). Among 8,304 participants, 5,296 (63.8%) were cumulatively seropositive for SARS-CoV-2 antibodies from September 2021 through September 2022. SARS-CoV-2 seroprevalence primarily increased from September 2021 to September 2022 in three districts (Lusaka: 61.8-100.0%, Chongwe: 39.6-94.7%, Chipata: 56.5-95.0%), but in Chadiza, seroprevalence increased from 27.8% in September 2021 to 77.2% in April 2022 before gradually dropping to 56.6% in July 2022. Among 5,906 participants with a valid COVID-19 vaccination status, infection alone accounted for antibody responses in 77.7% (4,590) of participants. Most women attending ANC had evidence of prior SARS-CoV-2 infection and most SARS-CoV-2 seropositivity was infection-induced. Capturing COVID-19 vaccination status and using a multiplex bead assay with anti-nucleocapsid and anti-RBD targets facilitated distinguishing infection-induced versus vaccine-induced antibody responses during a period of increasing COVID-19 vaccine coverage in Zambia. Declining seroprevalence in Chadiza may indicate waning antibodies and a need for booster vaccines. ANC clinics have a potential role in ongoing SARS-CoV-2 serosurveillance and can continue to provide insights into SARS-CoV-2 antibody dynamics to inform near real-time public health responses., Competing Interests: The authors have declared that no competing interests exist., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)
- Published
- 2024
- Full Text
- View/download PDF
4. Using antenatal care as a platform for malaria surveillance data collection: study protocol.
- Author
-
Gutman JR, Mwesigwa JN, Arnett K, Kangale C, Aaron S, Babarinde D, Buekens J, Candrinho B, Debe S, Digre P, Drake M, Gansané A, Gogue C, Griffith KS, Hicks J, Kinda R, Koenker H, Lemwayi R, Munsey A, Obi E, Ogouyèmi-Hounto A, Okoko OO, Onikpo F, Onoja A, Porter T, Savaio B, Tynuv K, Uhomoibhi P, Wagman J, Wolf K, Zulliger R, Walker P, Miller JM, and Robertson M
- Subjects
- Pregnancy, Female, Humans, Cross-Sectional Studies, Gravidity, Tanzania epidemiology, Observational Studies as Topic, Prenatal Care, Malaria diagnosis, Malaria epidemiology, Malaria prevention & control
- Abstract
Background: While many malaria-endemic countries have health management information systems that can measure and report malaria trends in a timely manner, these routine systems have limitations. Periodic community cross-sectional household surveys are used to estimate malaria prevalence and intervention coverage but lack geographic granularity and are resource intensive. Incorporating malaria testing for all women at their first antenatal care (ANC) visit (i.e., ANC1) could provide a more timely and granular source of data for monitoring trends in malaria burden and intervention coverage. This article describes a protocol designed to assess if ANC-based surveillance could be a pragmatic tool to monitor malaria., Methods: This is an observational, cross-sectional study conducted in Benin, Burkina Faso, Mozambique, Nigeria, Tanzania, and Zambia. Pregnant women attending ANC1 in selected health facilities will be tested for malaria infection by rapid diagnostic test and administered a brief questionnaire to capture key indicators of malaria control intervention coverage and care-seeking behaviour. In each location, contemporaneous cross-sectional household surveys will be leveraged to assess correlations between estimates obtained using each method, and the use of ANC data as a tool to track trends in malaria burden and intervention coverage will be validated., Results: This study will assess malaria prevalence at ANC1 aggregated at health facility and district levels, and by gravidity relative to current pregnancy (i.e., gravida 1, gravida 2, and gravida 3 +). ANC1 malaria prevalence will be presented as monthly trends. Additionally, correlation between ANC1 and household survey-derived estimates of malaria prevalence, bed net ownership and use, and care-seeking will be assessed., Conclusion: ANC1-based surveillance has the potential to provide a cost-effective, localized measure of malaria prevalence that is representative of the general population and useful for tracking monthly changes in parasite prevalence, as well as providing population-representative estimates of intervention coverage and care-seeking behavior. This study will evaluate the representativeness of these measures and collect information on operational feasibility, usefulness for programmatic decision-making, and potential for scale-up of malaria ANC1 surveillance., (© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)
- Published
- 2023
- Full Text
- View/download PDF
5. Comprehensive sexuality education linked to sexual and reproductive health services reduces early and unintended pregnancies among in-school adolescent girls in Zambia.
- Author
-
Mbizvo MT, Kasonda K, Muntalima NC, Rosen JG, Inambwae S, Namukonda ES, Mungoni R, Okpara N, Phiri C, Chelwa N, and Kangale C
- Subjects
- Pregnancy, Humans, Adolescent, Female, Pregnancy, Unplanned, Zambia, Cross-Sectional Studies, Sexual Behavior, Reproductive Health education, Sex Education, Reproductive Health Services
- Abstract
Background: Advancing the health of adolescents, particularly their sexual and reproductive health, including HIV prevention and care, is a development imperative. A critical part for improving their wellbeing and economic development is the social status accorded to adolescent girls and young women (AGYW). However, AGYW in many countries including Zambia, encounter health challenges that stem from gender inequalities, lack of empowerment, inaccurate knowledge on sexuality, and poor access to sexual and reproductive health (SRH) services and information. Addressing the knowledge gaps through comprehensive sexuality education (CSE) and improving access to SRH services and appropriate information, should reduce school attrition from early and unintended pregnancies (EUP) and enhance realization of their full potential., Methods: The aim was to reduce EUP and improve SRH outcomes among AGYW in Zambia through provision of CSE linked to receptive SRH services. A 3-Arm randomized control study collected cross-sectional data at baseline, midline and Endline. Schools where CSE was being routinely provided were randomized into a non-intervention arm (arm1), an intervention arm in which information on available SRH services was provided in schools by health workers to complement CSE, (arm 2), and arm 3 in which pupils receiving CSE were also encouraged or supported to access pre-sensitized, receptive SRH services., Results: Following 3 years of intervention exposure (CSE-Health Facility linkages), findings showed a significant decline of in-school pregnancies amongst AGYW in both intervention arms, with arm two exhibiting a more significant decline, having recorded only 0.74% pregnancies at endline (p < 0.001), as well as arm 3, which recorded 1.34% pregnancies (p < 0.001). No significant decline was recorded in the CSE only control arm. Trends in decline of pregnancies started to show by midline, and persisted at endline (2020), and when difference in differences test was applied, the incident rate ratios (IRR) between the none and exposed arms were equally significant (p < 0.001)., Conclusion: Linking provision of CSE with accessible SRH services that are receptive to needs of adolescents and young people reduces EUP, which provides the opportunity for higher retention in school for adolescent girls., (© 2023. The Author(s).)
- Published
- 2023
- Full Text
- View/download PDF
6. The Effect of Auricular Acupressure on Sleep Disturbance Among Patients With Leukemia: A Feasibility Study.
- Author
-
Liu XR, Rana N, Wong NS, James C, Lu J, and Xu X
- Subjects
- Acupressure methods, Acupressure statistics & numerical data, Adult, Drug Therapy methods, Drug Therapy psychology, Feasibility Studies, Female, Humans, Leukemia psychology, Male, Middle Aged, Sleep Wake Disorders psychology, Treatment Outcome, Acupressure standards, Joint Capsule, Leukemia therapy, Sleep Wake Disorders therapy
- Abstract
Auricular acupressure (AA) is widely used in East Asia and Europe to manage patients with sleep disturbance. This feasibility study was performed to demonstrate the potential of AA for sleep disturbance in patients with leukemia. Thirty-two patients with leukemia with poor sleep quality received AA 3 times a day for a total of 4 weeks. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality at baseline, at a 2-week intervention, and after a 4-week intervention. Compared with baseline scores, PSQI scores and the use of sleep medicine were significantly improved at week 2 and week 4 (P < .05). As a potential safety therapy, AA could be an alternative or complementary intervention to improve sleep quality for patients with leukemia with sleep disturbance.
- Published
- 2020
- Full Text
- View/download PDF
7. EGFR/ARF6 regulation of Hh signalling stimulates oncogenic Ras tumour overgrowth.
- Author
-
Chabu C, Li DM, and Xu T
- Subjects
- ADP-Ribosylation Factor 6, ADP-Ribosylation Factors metabolism, Animals, Cell Line, Tumor, Disease Models, Animal, Drosophila Proteins metabolism, Drosophila melanogaster metabolism, Epithelial Cells metabolism, Epithelial Cells pathology, ErbB Receptors metabolism, Genes, Reporter, Green Fluorescent Proteins genetics, Green Fluorescent Proteins metabolism, Hedgehog Proteins metabolism, Humans, IMP Dehydrogenase metabolism, Imaginal Discs metabolism, Imaginal Discs pathology, Larva genetics, Larva metabolism, Neoplasms metabolism, Neoplasms pathology, Receptors, Invertebrate Peptide metabolism, Signal Transduction, ADP-Ribosylation Factors genetics, Drosophila Proteins genetics, Drosophila melanogaster genetics, ErbB Receptors genetics, Gene Expression Regulation, Neoplastic, Hedgehog Proteins genetics, IMP Dehydrogenase genetics, Neoplasms genetics, Receptors, Invertebrate Peptide genetics
- Abstract
Multiple signalling events interact in cancer cells. Oncogenic Ras cooperates with Egfr, which cannot be explained by the canonical signalling paradigm. In turn, Egfr cooperates with Hedgehog signalling. How oncogenic Ras elicits and integrates Egfr and Hedgehog signals to drive overgrowth remains unclear. Using a Drosophila tumour model, we show that Egfr cooperates with oncogenic Ras via Arf6, which functions as a novel regulator of Hh signalling. Oncogenic Ras induces the expression of Egfr ligands. Egfr then signals through Arf6, which regulates Hh transport to promote Hh signalling. Blocking any step of this signalling cascade inhibits Hh signalling and correspondingly suppresses the growth of both, fly and human cancer cells harbouring oncogenic Ras mutations. These findings highlight a non-canonical Egfr signalling mechanism, centered on Arf6 as a novel regulator of Hh signalling. This explains both, the puzzling requirement of Egfr in oncogenic Ras-mediated overgrowth and the cooperation between Egfr and Hedgehog.
- Published
- 2017
- Full Text
- View/download PDF
8. A Meiotic Drive Element in the Maize Pathogen Fusarium verticillioides Is Located Within a 102 kb Region of Chromosome V.
- Author
-
Pyle J, Patel T, Merrill B, Nsokoshi C, McCall M, Proctor RH, Brown DW, and Hammond TM
- Subjects
- Crosses, Genetic, Fungal Proteins genetics, Fusarium pathogenicity, Gene Expression Regulation, Fungal, Genome, Fungal, Polymorphism, Restriction Fragment Length, Polymorphism, Single Nucleotide, Spores, Fungal genetics, Chromosomes, Fungal, Fusarium genetics, Meiosis, Zea mays microbiology
- Abstract
Fusarium verticillioides is an agriculturally important fungus because of its association with maize and its propensity to contaminate grain with toxic compounds. Some isolates of the fungus harbor a meiotic drive element known as Spore killer (Sk(K)) that causes nearly all surviving meiotic progeny from an Sk(K) × Spore killer-susceptible (Sk(S)) cross to inherit the Sk(K) allele. Sk(K) has been mapped to chromosome V but the genetic element responsible for meiotic drive has yet to be identified. In this study, we used cleaved amplified polymorphic sequence markers to genotype individual progeny from an Sk(K) × Sk(S) mapping population. We also sequenced the genomes of three progeny from the mapping population to determine their single nucleotide polymorphisms. These techniques allowed us to refine the location of Sk(K) to a contiguous 102 kb interval of chromosome V, herein referred to as the Sk region. Relative to Sk(S) genotypes, Sk(K) genotypes have one extra gene within this region for a total of 42 genes. The additional gene in Sk(K) genotypes, herein named SKC1 for Spore Killer Candidate 1, is the most highly expressed gene from the Sk region during early stages of sexual development. The Sk region also has three hyper-variable regions, the longest of which includes SKC1 The possibility that SKC1, or another gene from the Sk region, is an essential component of meiotic drive and spore killing is discussed., (Copyright © 2016 Pyle et al.)
- Published
- 2016
- Full Text
- View/download PDF
9. Mutations in KATNB1 Cause Complex Cerebral Malformations by Disrupting Asymmetrically Dividing Neural Progenitors.
- Author
-
Mishra-Gorur K, Çağlayan AO, Schaffer AE, Chabu C, Henegariu O, Vonhoff F, Akgümüş GT, Nishimura S, Han W, Tu S, Baran B, Gümüş H, Dilber C, Zaki MS, Hossni HAA, Rivière JB, Kayserili H, Spencer EG, Rosti RÖ, Schroth J, Per H, Çağlar C, Çağlar Ç, Dölen D, Baranoski JF, Kumandaş S, Minja FJ, Erson-Omay EZ, Mane SM, Lifton RP, Xu T, Keshishian H, Dobyns WB, Chi NC, Šestan N, Louvi A, Bilgüvar K, Yasuno K, Gleeson JG, and Günel M
- Published
- 2015
- Full Text
- View/download PDF
10. Mutations in KATNB1 cause complex cerebral malformations by disrupting asymmetrically dividing neural progenitors.
- Author
-
Mishra-Gorur K, Çağlayan AO, Schaffer AE, Chabu C, Henegariu O, Vonhoff F, Akgümüş GT, Nishimura S, Han W, Tu S, Baran B, Gümüş H, Dilber C, Zaki MS, Hossni HA, Rivière JB, Kayserili H, Spencer EG, Rosti RÖ, Schroth J, Per H, Çağlar C, Çağlar Ç, Dölen D, Baranoski JF, Kumandaş S, Minja FJ, Erson-Omay EZ, Mane SM, Lifton RP, Xu T, Keshishian H, Dobyns WB, Chi NC, Šestan N, Louvi A, Bilgüvar K, Yasuno K, Gleeson JG, and Günel M
- Subjects
- Animals, Brain growth & development, Cell Count, Cell Division genetics, Dendrites genetics, Drosophila, Drosophila Proteins genetics, Humans, Katanin, Mice, Microcephaly pathology, Microtubule-Associated Proteins genetics, Mutation, Spindle Apparatus genetics, Zebrafish, Adenosine Triphosphatases genetics, Brain abnormalities, Brain pathology, Microcephaly genetics, Neural Stem Cells pathology, Neurogenesis genetics, Optic Lobe, Nonmammalian abnormalities
- Abstract
Exome sequencing analysis of over 2,000 children with complex malformations of cortical development identified five independent (four homozygous and one compound heterozygous) deleterious mutations in KATNB1, encoding the regulatory subunit of the microtubule-severing enzyme Katanin. Mitotic spindle formation is defective in patient-derived fibroblasts, a consequence of disrupted interactions of mutant KATNB1 with KATNA1, the catalytic subunit of Katanin, and other microtubule-associated proteins. Loss of KATNB1 orthologs in zebrafish (katnb1) and flies (kat80) results in microcephaly, recapitulating the human phenotype. In the developing Drosophila optic lobe, kat80 loss specifically affects the asymmetrically dividing neuroblasts, which display supernumerary centrosomes and spindle abnormalities during mitosis, leading to cell cycle progression delays and reduced cell numbers. Furthermore, kat80 depletion results in dendritic arborization defects in sensory and motor neurons, affecting neural architecture. Taken together, we provide insight into the mechanisms by which KATNB1 mutations cause human cerebral cortical malformations, demonstrating its fundamental role during brain development., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
11. Oncogenic Ras stimulates Eiger/TNF exocytosis to promote growth.
- Author
-
Chabu C and Xu T
- Subjects
- Animals, Blotting, Western, Cell Proliferation physiology, DNA Primers genetics, Drosophila metabolism, Immunoprecipitation, Microscopy, Fluorescence, Real-Time Polymerase Chain Reaction, Signal Transduction physiology, Drosophila growth & development, Drosophila Proteins metabolism, Exocytosis physiology, Membrane Proteins metabolism, Tumor Necrosis Factor-alpha metabolism, ras Proteins metabolism
- Abstract
Oncogenic mutations in Ras deregulate cell death and proliferation to cause cancer in a significant number of patients. Although normal Ras signaling during development has been well elucidated in multiple organisms, it is less clear how oncogenic Ras exerts its effects. Furthermore, cancers with oncogenic Ras mutations are aggressive and generally resistant to targeted therapies or chemotherapy. We identified the exocytosis component Sec15 as a synthetic suppressor of oncogenic Ras in an in vivo Drosophila mosaic screen. We found that oncogenic Ras elevates exocytosis and promotes the export of the pro-apoptotic ligand Eiger (Drosophila TNF). This blocks tumor cell death and stimulates overgrowth by activating the JNK-JAK-STAT non-autonomous proliferation signal from the neighboring wild-type cells. Inhibition of Eiger/TNF exocytosis or interfering with the JNK-JAK-STAT non-autonomous proliferation signaling at various steps suppresses oncogenic Ras-mediated overgrowth. Our findings highlight important cell-intrinsic and cell-extrinsic roles of exocytosis during oncogenic growth and provide a new class of synthetic suppressors for targeted therapy approaches., (© 2014. Published by The Company of Biologists Ltd.)
- Published
- 2014
- Full Text
- View/download PDF
12. Twins/PP2A regulates aPKC to control neuroblast cell polarity and self-renewal.
- Author
-
Chabu C and Doe CQ
- Subjects
- Animals, Catalytic Domain, Drosophila embryology, Immunoprecipitation, Cell Polarity, Protein Kinase C metabolism, Protein Phosphatase 2 metabolism
- Abstract
Asymmetric cell division is a mechanism for generating cell diversity as well as maintaining stem cell homeostasis in both Drosophila and mammals. In Drosophila, larval neuroblasts are stem cell-like progenitors that divide asymmetrically to generate neurons of the adult brain. Mitotic neuroblasts localize atypical protein kinase C (aPKC) to their apical cortex. Cortical aPKC excludes cortical localization of Miranda and its cargo proteins Prospero and Brain tumor, resulting in their partitioning into the differentiating, smaller ganglion mother cell (GMC) where they are required for neuronal differentiation. In addition to aPKC, the kinases Aurora-A and Polo also regulate neuroblast self-renewal, but the phosphatases involved in neuroblast self-renewal have not been identified. Here we report that aPKC is in a protein complex in vivo with Twins, a Drosophila B-type protein phosphatase 2A (PP2A) subunit, and that Twins and the catalytic subunit of PP2A, called Microtubule star (Mts), are detected in larval neuroblasts. Both Twins and Mts are required to exclude aPKC from the basal neuroblast cortex: twins mutant brains, twins mutant single neuroblast mutant clones, or mts dominant negative single neuroblast clones all show ectopic basal cortical localization of aPKC. Consistent with ectopic basal aPKC is the appearance of supernumerary neuroblasts in twins mutant brains or twins mutant clones. We conclude that Twins/PP2A is required to maintain aPKC at the apical cortex of mitotic neuroblasts, keeping it out of the differentiating GMC, and thereby maintaining neuroblast homeostasis.
- Published
- 2009
- Full Text
- View/download PDF
13. Dap160/intersectin binds and activates aPKC to regulate cell polarity and cell cycle progression.
- Author
-
Chabu C and Doe CQ
- Subjects
- Animals, Cell Cycle physiology, Cell Polarity physiology, Drosophila cytology, Drosophila growth & development, Drosophila Proteins genetics, Enzyme Activation, Larva, Mutation, Protein Binding, Protein Kinase C genetics, Vesicular Transport Proteins genetics, Drosophila embryology, Drosophila Proteins physiology, Neurons physiology, Protein Kinase C metabolism, Stem Cells physiology, Vesicular Transport Proteins physiology
- Abstract
The atypical protein kinase C (aPKC) is required for cell polarization of many cell types, and is upregulated in several human tumors. Despite its importance in cell polarity and growth control, relatively little is known about how aPKC activity is regulated. Here, we use a biochemical approach to identify Dynamin-associated protein 160 (Dap160; related to mammalian intersectin) as an aPKC-interacting protein in Drosophila. We show that Dap160 directly interacts with aPKC, stimulates aPKC activity in vitro and colocalizes with aPKC at the apical cortex of embryonic neuroblasts. In dap160 mutants, aPKC is delocalized from the neuroblast apical cortex and has reduced activity, based on its inability to displace known target proteins from the basal cortex. Both dap160 and aPKC mutants have fewer proliferating neuroblasts and a prolonged neuroblast cell cycle. We conclude that Dap160 positively regulates aPKC activity and localization to promote neuroblast cell polarity and cell cycle progression.
- Published
- 2008
- Full Text
- View/download PDF
14. Cdc42 acts downstream of Bazooka to regulate neuroblast polarity through Par-6 aPKC.
- Author
-
Atwood SX, Chabu C, Penkert RR, Doe CQ, and Prehoda KE
- Subjects
- Adaptor Proteins, Signal Transducing genetics, Animals, Cell Division physiology, Central Nervous System cytology, Drosophila Proteins genetics, Drosophila melanogaster, GTP-Binding Proteins genetics, Genes, Dominant, Intracellular Signaling Peptides and Proteins genetics, Intracellular Signaling Peptides and Proteins metabolism, Mice, Mice, Knockout, Mutation, Organ Specificity physiology, Protein Binding physiology, Protein Kinase C genetics, Protein Transport physiology, Stem Cells cytology, cdc42 GTP-Binding Protein genetics, Adaptor Proteins, Signal Transducing metabolism, Cell Polarity physiology, Central Nervous System embryology, Drosophila Proteins metabolism, GTP-Binding Proteins metabolism, Protein Kinase C metabolism, Stem Cells metabolism, cdc42 GTP-Binding Protein metabolism
- Abstract
Cdc42 recruits Par-6-aPKC to establish cell polarity from worms to mammals. Although Cdc42 is reported to have no function in Drosophila neuroblasts, a model for cell polarity and asymmetric cell division, we show that Cdc42 colocalizes with Par-6-aPKC at the apical cortex in a Bazooka-dependent manner, and is required for Par-6-aPKC localization. Loss of Cdc42 disrupts neuroblast polarity: cdc42 mutant neuroblasts have cytoplasmic Par-6-aPKC, and this phenotype is mimicked by neuroblast-specific expression of a dominant-negative Cdc42 protein or a Par-6 protein that lacks Cdc42-binding ability. Conversely, expression of constitutively active Cdc42 leads to ectopic Par-6-aPKC localization and corresponding cell polarity defects. Bazooka remains apically enriched in cdc42 mutants. Robust Cdc42 localization requires Par-6, indicating the presence of feedback in this pathway. In addition to regulating Par-6-aPKC localization, Cdc42 increases aPKC activity by relieving Par-6 inhibition. We conclude that Cdc42 regulates aPKC localization and activity downstream of Bazooka, thereby directing neuroblast cell polarity and asymmetric cell division.
- Published
- 2007
- Full Text
- View/download PDF
15. Scribble protein domain mapping reveals a multistep localization mechanism and domains necessary for establishing cortical polarity.
- Author
-
Albertson R, Chabu C, Sheehan A, and Doe CQ
- Subjects
- Animals, Blotting, Western, Body Patterning, Cell Cycle Proteins chemistry, Cell Proliferation, Drosophila Proteins metabolism, Drosophila melanogaster metabolism, Epithelial Cells cytology, Epithelial Cells metabolism, Epithelium metabolism, Gene Deletion, Genotype, Histones chemistry, Immunohistochemistry, Leucine chemistry, Membrane Proteins metabolism, Microscopy, Fluorescence, Mitosis, Neurons metabolism, Phenotype, Polymerase Chain Reaction, Protein Structure, Tertiary, Spindle Apparatus metabolism, Drosophila Proteins chemistry, Membrane Proteins chemistry
- Abstract
The Drosophila tumor suppressor protein Scribble is required for epithelial polarity, neuroblast polarity, neuroblast spindle asymmetry and limiting cell proliferation. It is a member of the newly described LAP protein family, containing 16 leucine rich repeats (LRRs), four PDZ domains and an extensive carboxyl-terminal (CT) domain. LRR and PDZ domains mediate protein-protein interactions, but little is know about their function within LAP family proteins. We have determined the role of the LRR, PDZ and CT domains for Scribble localization in neuroblasts and epithelia, and for Scribble function in neuroblasts. We found that the LRR and PDZ domains are both required for proper targeting of Scribble to septate junctions in epithelia; that the LRR domain is necessary and sufficient for cortical localization in mitotic neuroblasts, and that the PDZ2 domain is required for efficient cortical and apical localization of Scribble in neuroblasts. In addition, we show that the LRR domain is sufficient to target Miranda protein to the neuroblast cortex, but that LRR+PDZ will exclude Miranda from the cortex. Our results highlight the importance of both LRR and PDZ domains for the proper localization and function of Scribble in neuroblasts.
- Published
- 2004
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.