A5059014336- Microtubule and mitosis dynamics
- Fungal and yeast genetics research
- RNA Research and Splicing
- Mitochondrial Function and Pathology
- Gene Regulatory Network Analysis
- Protist diversity and phylogeny
- Cellular Mechanics and Interactions
- RNA and protein synthesis mechanisms
- Ubiquitin and proteasome pathways
- Hippo pathway signaling and YAP/TAZ
- Plant Reproductive Biology
- Evolution and Genetic Dynamics
- Advanced biosensing and bioanalysis techniques
- Cancer-related gene regulation
- RNA modifications and cancer
- Photosynthetic Processes and Mechanisms
- Cellular transport and secretion
- Carbon and Quantum Dots Applications
- Mechanisms of cancer metastasis
- Biofuel production and bioconversion
- Muscle Physiology and Disorders
- 14-3-3 protein interactions
- Entomopathogenic Microorganisms in Pest Control
- Biotin and Related Studies
- Prion Diseases and Protein Misfolding
University of Miami
2012-2025
Duke University
2019
Marine Biological Laboratory
2012-2016
Woods Hole Oceanographic Institution
2015
The Honourable Society of Lincoln's Inn
1995-1998
University of California, San Diego
1996
Cancer Research UK
1996
Institut de Biologie Structurale
1992
CEA Grenoble
1992
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
1992
In eukaryotic cells, the onset of mitosis involves cyclin molecules which interact with proteins cdc2 family to produce active kinases. vertebrate A dependent kinases become in S- and pro-phases, whereas a B-dependent kinase is mostly metaphase. It has recently been shown that, when added Xenopus egg extracts, bacterially produced A- B-type cyclins associate predominantly same catalytic subunit, namely p34cdc2, induce its histone H1 activity different kinetics. Here, we show that cell free...
Taxol, a microtubule stabilizing drug, induces the formation of numerous asters in cytoplasm mitotic cells (De Brabander, M., G. Geuens, R. Nuydens, Willebrords, J. DeMey. 1981. Proc. Natl. Acad. Sci. USA. 78:5608-5612). The center these share with spindle poles some characteristics such as presence centrosomal material and calmodulin. We have recently reproduced assembly taxol cell-free system (Buendia, B., C. Antony, F. Verde, M. Bornens, E. Karsenti. 1990. Cell 97:259-271) using extracts...
We have used cryo-electron microscopy of vitrified specimens to study microtubules assembled both from three cycle purified tubulin (3x-tubulin) and in cell free extracts Xenopus eggs. In vitro 3x-tubulin samples a majority with 14 protofilaments whereas most 13 protofilaments. Microtubule polymorphism was observed cases. The number can change abruptly along individual usually by single increments but double also occur. For 3x-tubulin, increasing the magnesium concentration decreases...
To identify new genes involved in the control of cell morphogenesis fission yeast Schizosaccharomyces pombe we have visually screened for temperature-sensitive mutants that show defects morphology. We isolated and characterized 64 defining 19 independent genes, 10 which not been previously described. One class mutants, 12 orb become round a complete loss polarity. A second exhibits branched or bent morphologies. These either selection growth site, two tea maintenance direction, five ban...
The molecular mechanisms that coordinate cell morphogenesis with the cycle remain largely unknown. We have investigated this process in fission yeast where changes polarized growth are coupled progression. orb6 gene is required during interphase to maintain polarity and encodes a serine/threonine protein kinase, belonging myotonic dystrophy kinase/ cot1 / warts family. A decrease Orb6 levels leads loss of shape mitotic advance, whereas an increase maintains delays mitosis by affecting p34...
Pole to How do fission yeast cells decide when grow at a single end (or pole) of the cell or whether in multipolar manner? Das et al. (p. 239 , published online 17 May) found that accumulation active form small guanine nucleotide–binding protein Cdc42 growing tip oscillated with period few minutes. In one pole, oscillations were primarily present pole and during bipolar growth symmetrical anticorrelated observed. Dynamic competition for between multiple zones could represent flexible...
The Schizosaccharomyces pombe mutant, ban5-4, displays aberrant mitochondrial distribution. Incubation of this conditional-lethal mutant at the nonpermissive temperature led to aggregated mitochondria that were distributed asymmetrically within cell. Development asymmetry but not aggregation required progression through cell division cycle. Genetic analysis revealed ban5-4 is an allele atb2 encoding alpha 2-tubulin. Consistent with finding, cells cold-sensitive nda3 mutation in beta-tubulin...
The plus ends of microtubules have been speculated to regulate the actin cytoskeleton for proper positioning sites cell polarization and cytokinesis. In fission yeast Schizosaccharomyces pombe, interphase kelch repeat protein tea1p polarized growth. Here, we show that is directly deposited at tips by microtubule ends. Tea1p associates in large “polarisome” complexes with bud6p for3p, a formin assembles cables. also interacts separate complex CLIP-170 tip1p, end–binding anchors end....
Control of cellular dimensions and cell symmetry are critical for development differentiation. Here we provide evidence that the putative Rho-GAP Rga4p Schizosaccharomyces pombe controls dimensions. rga4 Delta cells wider in diameter shorter length, whereas overexpression leads to reduced growing tip. Consistent with a negative role growth control, protein localizes sides "corset" pattern, nongrowing tips. Additionally, show an altered pattern similar observed mutants formin homology For3p....
Cdc42 is a Rho-family GTPase that controls cell polarization from yeast to human cells. In fission yeast, under normal growth conditions, Cdc42-GTP oscillates between tips promote polarized growth. However, when exposed environmental stressors, adopts an "exploratory" pattern of activation along the membrane. This also occurs NDR kinase Orb6 downregulated. Here, we describe molecular mechanism behind emergence exploratory dynamics and identify new substrate kinase, GAP Rga3. Additionally,...
The molecular mechanisms that temporally and spatially coordinate cell morphogenesis with the cycle remain poorly understood. Here we describe characterization of fission yeast Mob2p, a novel protein required for regulating polarity control. Deletion mob2 is lethal causes cells to become spherical, depolarized actin microtubule cytoskeletons. A decrease in Mob2p level results defect activation bipolar growth. This phenotype identical mutants defective orb6 kinase gene, find physically...
Active Cdc42 GTPase, a key regulator of cell polarity, displays oscillatory dynamics that are anticorrelated at the two tips in fission yeast. Anticorrelation suggests competition for active or its effectors. Here we show how 14-3-3 protein Rad24 associates with guanine exchange factor (GEF) Gef1, limiting Gef1 availability to promote activation. Phosphorylation by conserved NDR kinase Orb6 promotes binding Rad24. Loss Rad24-Gef1 interaction increases localization and activation reduces...
An ideal vehicle with a high transfection efficiency is crucial for gene delivery. In this study, type of cationic carbon dot (CCD) known as APCDs were first prepared arginine (Arg) and pentaethylenehexamine (PEHA) precursors conjugated oleic acid (OA) By tuning the mass ratio to OA, APCDs-OA conjugates, namely, APCDs-0.5OA, APCDs-1.0OA, APCDs-1.5OA synthesized. All three amphiphilic conjugates show affinity DNA through electrostatic interactions. APCDs-0.5OA exhibit strong binding small...
A monoclonal antibody (CTR2611) raised against centrosomes isolated from human lymphocytes (KE37) stains the pericentriolar material and intermediate filaments in same cells. In MDCK cells, where most of microtubules do not originate region during interphase, antigen is distributed along filaments. At onset mitosis, a large fraction CTR2611 associates with minus-end domain mitotic spindle but itself. Treatment cells taxol leads to assembly many microtubule asters cytoplasm at expense...
RNA-binding proteins contribute to the formation of ribonucleoprotein (RNP) granules by phase transition, but regulatory mechanisms are not fully understood. Conserved fission yeast NDR (Nuclear Dbf2-Related) kinase Orb6 governs cell morphogenesis in part spatially controlling Cdc42 GTPase. Here we describe a novel, independent function for negatively regulating recruitment protein Sts5 into RNPs promote polarized growth. We find that inhibits granules, its association with processing (P)...
The p21-activated kinase (PAK) homolog, Shk1, is a critical component of multifunctional Ras/Cdc42/PAK complex required for viability, polarized growth and cell shape, sexual differentiation in the fission yeast, Schizosaccharomyces pombe. Substrate targets Shk1 have not previously been described. Here we show that S. pombe polarity factor, Tea1, directly phosphorylated by vitro. We demonstrate further Tea1 cells its level phosphorylation significantly reduced defective function. Consistent...
The p21-activated kinase, Shk1, is required for cell viability, establishment and maintenance of polarity, proper mating response in the fission yeast,Schizosaccharomyces pombe. Previous genetic studies suggested that a presumptive protein methyltransferase, Skb1, functions as positive modulator Shk1. However, unlike Skb1 not viability or S. pombe cells contributes only modestly to regulation morphology under normal growth conditions. Here we demonstrate plays more significant role...
Adaptation to the nutritional environment is critical for all cells. RAS GTPase a highly conserved GTP-binding protein with crucial functions cell growth and differentiation in response environmental conditions. Here, we describe novel mechanism connecting nutrient availability fission yeast. We report that NDR/LATS kinase Orb6 responds cues regulates Ras1 activity. increases levels of an activator, guanine nucleotide exchange factor Efc25, by phosphorylating Sts5, bound efc25 mRNA. By...