The Melaminophenyl Arsenicals Melarsoprol and Melarsen Oxide Interfere with Thiamine Metabolism in the Fission Yeast Schizosaccharomyces pombe

ABSTRACT The melaminophenyl arsenical melarsoprol is the main drug used against late-stage sleeping sickness caused by Trypanosoma brucei subspecies. Its active metabolite in the human body is melarsen oxide. Here, it is shown that this metabolite inhibits growth of the fission yeast Schizosaccharomyces pombe and that its toxicity can be abolished efficiently by thiamine (vitamin B1), thiamine analogues, and the pyrimidine moiety of the thiamine molecule. Uptake of melarsen oxide is mediated by a membrane protein (car1p), which is involved in the uptake of thiamine and its pyrimidine moiety. Melarsoprol is taken up by cells in a thiamine- and car1p-dependent manner but is not toxic to cells.

Download Full-text

Alp7-Mto1 and Alp14 synergize to promote interphase microtubule regrowth from the nuclear envelope

Journal of Molecular Cell Biology ◽

10.1093/jmcb/mjz038 ◽

2019 ◽

Vol 11 (11) ◽

pp. 944-955 ◽

Cited By ~ 2

Author(s):

Wenyue Liu ◽

Fan Zheng ◽

Yucai Wang ◽

Chuanhai Fu

Keyword(s):

Nuclear Envelope ◽

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Microtubule Assembly ◽

Dependent Manner ◽

Microtubule Nucleation ◽

Microtubule Organizing Centers ◽

Evolutionarily Conserved ◽

Microtubule Growth ◽

In Cells

Abstract Microtubules grow not only from the centrosome but also from various noncentrosomal microtubule-organizing centers (MTOCs), including the nuclear envelope (NE) and pre-existing microtubules. The evolutionarily conserved proteins Mto1/CDK5RAP2 and Alp14/TOG/XMAP215 have been shown to be involved in promoting microtubule nucleation. However, it has remained elusive as to how the microtubule nucleation promoting factors are specified to various noncentrosomal MTOCs, particularly the NE, and how these proteins coordinate to organize microtubule assembly. Here, we demonstrate that in the fission yeast Schizosaccharomyces pombe, efficient interphase microtubule growth from the NE requires Alp7/TACC, Alp14/TOG/XMAP215, and Mto1/CDK5RAP2. The absence of Alp7, Alp14, or Mto1 compromises microtubule regrowth on the NE in cells undergoing microtubule repolymerization. We further demonstrate that Alp7 and Mto1 interdependently localize to the NE in cells without microtubules and that Alp14 localizes to the NE in an Alp7 and Mto1-dependent manner. Tethering Mto1 to the NE in cells lacking Alp7 partially restores microtubule number and the efficiency of microtubule generation from the NE. Hence, our study delineates that Alp7, Alp14, and Mto1 work in concert to regulate interphase microtubule regrowth on the NE.

Download Full-text

Amiloride Uptake and Toxicity in Fission Yeast Are Caused by the Pyridoxine Transporter Encoded by bsu1+ (car1+)

Eukaryotic Cell ◽

10.1128/ec.4.2.319-326.2005 ◽

2005 ◽

Vol 4 (2) ◽

pp. 319-326 ◽

Cited By ~ 16

Author(s):

Jürgen Stolz ◽

Heike J. P. Wöhrmann ◽

Christian Vogl

Keyword(s):

Saccharomyces Cerevisiae ◽

Plasma Membrane ◽

Multidrug Resistance ◽

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Vitamin B ◽

Acidic Ph ◽

Ph Optimum ◽

Sodium Transporters ◽

High Affinity

ABSTRACT Amiloride, a diuretic drug that acts by inhibition of various sodium transporters, is toxic to the fission yeast Schizosaccharomyces pombe. Previous work has established that amiloride sensitivity is caused by expression of car1 +, which encodes a protein with similarity to plasma membrane drug/proton antiporters from the multidrug resistance family. Here we isolated car1 + by complementation of Saccharomyces cerevisiae mutants that are deficient in pyridoxine biosynthesis and uptake. Our data show that Car1p represents a new high-affinity, plasma membrane-localized import carrier for pyridoxine, pyridoxal, and pyridoxamine. We therefore propose the gene name bsu1 + (for vitamin B6 uptake) to replace car1 +. Bsu1p displays an acidic pH optimum and is inhibited by various protonophores, demonstrating that the protein works as a proton symporter. The expression of bsu1 + is associated with amiloride sensitivity and pyridoxine uptake in both S. cerevisiae and S. pombe cells. Moreover, amiloride acts as a competitor of pyridoxine uptake, demonstrating that both compounds are substrates of Bsu1p. Taken together, our data show that S. pombe and S. cerevisiae possess unrelated plasma membrane pyridoxine transporters. The S. pombe protein may be structurally related to the unknown human pyridoxine transporter, which is also inhibited by amiloride.

Download Full-text

Functional expression and cellular localization of the Na+/H+ exchanger Sod2 of the fission yeast Schizosaccharomyces pombe

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y05-044 ◽

2005 ◽

Vol 83 (7) ◽

pp. 565-572 ◽

Cited By ~ 9

Author(s):

Larry Fliegel ◽

Christine Wiebe ◽

Gordon Chua ◽

Paul G Young

Keyword(s):

Plasma Membrane ◽

Membrane Protein ◽

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Cellular Localization ◽

Functional Expression ◽

Cation Binding ◽

Plasma Membrane Protein ◽

Gfp Fusion Protein ◽

Growing Cell

In the fission yeast Schizosaccharomyces pombe, the Na+/H+ exchanger, Sod2, plays a major role in the removal of excess intracellular sodium, and its disruption results in a sodium-sensitive phenotype. We examined the subcellular distribution and dynamics of Sod2 expression in S. pombe using a sod2-GFP fusion protein under the control of an attenuated version of the inducible nmt promoter. Sod2 was localized throughout the plasma membrane, the nuclear envelope, and some internal membrane systems. In exponentially growing cells, in which sod2-GFP was expressed and then the promoter turned-off, previously synthesized sod2-GFP was stable for long periods and found localized to the plasma membrane in the medial regions of the cell. It was not present at the actively growing cell ends. This suggests that these regions of the cell contain old plasma membrane protein vs. newly synthesized plasma membrane without Sod2 at the growing ends. Sod2 localization was not affected by salt stress. The results suggest that Sod2 is both a plasma membrane protein and is present in intracellular membranes. It is likely tethered within discrete regions of the plasma membrane and is not free to diffuse throughout the bilayer. Key words: Na+/H+ exchanger, Schizosaccharomyces pombe, cation binding, salt tolerance.

Download Full-text

The concerted actions of Tip1/CLIP-170, Klp5/Kinesin-8, and Alp14/XMAP215 regulate microtubule catastrophe at the cell end

Journal of Molecular Cell Biology ◽

10.1093/jmcb/mjz039 ◽

2019 ◽

Vol 11 (11) ◽

pp. 956-966 ◽

Cited By ~ 2

Author(s):

Xiaojia Niu ◽

Fan Zheng ◽

Chuanhai Fu

Keyword(s):

Cell Growth ◽

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Cell Polarity ◽

Residence Time ◽

Dependent Manner ◽

Spatial Regulation ◽

Live Cell Microscopy ◽

Stabilizing Factors ◽

Cell Microscopy

Abstract Spatial regulation of microtubule catastrophe is important for controlling microtubule length and consequently contributes to the proper establishment of cell polarity and cell growth. The +TIP proteins including Tip1/CLIP-170, Klp5/Kinesin-8, and Alp14/XMAP215 reside at microtubule plus ends to regulate microtubule dynamics. In the fission yeast Schizosaccharomyces pombe, Tip1 and Alp14 serve as microtubule-stabilizing factors, while Klp5 functions oppositely as a catastrophe-promoting factor. Despite that Tip1 has been shown to play a key role in restricting microtubule catastrophe to the cell end, how Tip1 fulfills the role remains to be determined. Employing live-cell microscopy, we showed that the absence of Tip1 impairs the localization of both Klp5 and Alp14 at microtubule plus ends, but the absence of Klp5 prolongs the residence time of Tip1 at microtubule plus ends. We further revealed that Klp5 accumulates behind Tip1 at microtubule plus ends in a Tip1-dependent manner. In addition, artificially tethering Klp5 to microtubule plus ends promotes premature microtubule catastrophe, while tethering Alp14 to microtubule plus ends in the cells lacking Tip1 rescues the phenotype of short microtubules. These findings establish that Tip1 restricts microtubule catastrophe to the cell end likely by spatially restricting the microtubule catastrophe activity of Klp5 and stabilizing Alp14 at microtubule plus ends. Thus, the work demonstrates the orchestration of Tip1, Alp14, and Klp5 in ensuring microtubule catastrophe at the cell end.

Download Full-text

Ascorbic acid supplementation suppresses cadmium-derived alterations in the fission yeast Schizosaccharomyces pombe

Potravinarstvo Slovak Journal of Food Sciences ◽

10.5219/1618 ◽

2021 ◽

Vol 15 ◽

pp. 423-432

Author(s):

Marek Kovár ◽

Alica Navrátilová ◽

Anna Trakovická ◽

Miroslava Požgajová

Keyword(s):

Ascorbic Acid ◽

Cell Growth ◽

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Membrane Lipids ◽

Cadmium Toxicity ◽

Model Organism ◽

Cell Types ◽

Dependent Manner ◽

The Impact

Cadmium (Cd) a highly toxic environmental pollutant, that does not have any physiological function in the organism, represents a great concern for human health as it can be easily transported from its environmental sources to the food chain. Food, water, and air are the major sources of Cd exposure to the population. Cd-mediated impairments of the basic cellular properties largely depend on its ability to enhance the formation of reactive oxygen species (ROS) and thus triggers oxidative stress to the cell. With the use of fission yeast Schizosaccharomyces pombe (S. pombe) as the model organism, we have analyzed the impact of Cd on the cell growth intensity, as it represents the fundamental feature of all living organisms. Cells were incubated with different Cd concentrations for 3, 6, and 9 hours to investigate the effect of Cd on cell growth in a time and dose-dependent manner. Further possible Cd-derived alterations, as the peroxidation of membrane lipids or the functional impairment of the enzymatic antioxidant protection mechanisms, were investigated by determination of the MDA content and via catalase (CAT) activity detection. Moreover, ascorbic acid (AsA) pre-treatment was subjected to investigate the assumed positive effect of AsA against Cd toxicity. We show here on one hand that cells suffer under the influence of Cd, but on the other hand, they substantially profit from AsA supplementation. Because S. pombe is known to shares many molecular, and biochemical similarities with higher organisms, the effect of AsA in cadmium toxicity elimination might be expected to a similar extent also in other cell types.

Download Full-text

A New Membrane Protein Sbg1 Links the Contractile Ring Apparatus and Septum Synthesis Machinery in Fission Yeast

PLoS Genetics ◽

10.1371/journal.pgen.1006383 ◽

2016 ◽

Vol 12 (10) ◽

pp. e1006383 ◽

Cited By ~ 23

Author(s):

Kriti Sethi ◽

Saravanan Palani ◽

Juan C. G. Cortés ◽

Mamiko Sato ◽

Mayalagu Sevugan ◽

...

Keyword(s):

Membrane Protein ◽

Fission Yeast ◽

Contractile Ring

Download Full-text

Correlation of membrane protein conformational and functional dynamics

Nature Communications ◽

10.1038/s41467-021-24660-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Raghavendar Reddy Sanganna Gari ◽

Joel José Montalvo‐Acosta ◽

George R. Heath ◽

Yining Jiang ◽

Xiaolong Gao ◽

...

Keyword(s):

Membrane Protein ◽

Conformational Changes ◽

Single Channel ◽

Conformational Dynamics ◽

Md Simulations ◽

High Temporal Resolution ◽

Dependent Manner ◽

Functional Dynamics ◽

Ph Dependent ◽

Open States

AbstractConformational changes in ion channels lead to gating of an ion-conductive pore. Ion flux has been measured with high temporal resolution by single-channel electrophysiology for decades. However, correlation between functional and conformational dynamics remained difficult, lacking experimental techniques to monitor sub-millisecond conformational changes. Here, we use the outer membrane protein G (OmpG) as a model system where loop-6 opens and closes the β-barrel pore like a lid in a pH-dependent manner. Functionally, single-channel electrophysiology shows that while closed states are favored at acidic pH and open states are favored at physiological pH, both states coexist and rapidly interchange in all conditions. Using HS-AFM height spectroscopy (HS-AFM-HS), we monitor sub-millisecond loop-6 conformational dynamics, and compare them to the functional dynamics from single-channel recordings, while MD simulations provide atomistic details and energy landscapes of the pH-dependent loop-6 fluctuations. HS-AFM-HS offers new opportunities to analyze conformational dynamics at timescales of domain and loop fluctuations.

Download Full-text

Upstream – News in Genomics

Comparative and Functional Genomics ◽

10.1002/cfg.172 ◽

2002 ◽

Vol 3 (3) ◽

pp. 221-225

Keyword(s):

Saccharomyces Cerevisiae ◽

Ovarian Cancer ◽

Oryza Sativa ◽

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Proteomic Analysis ◽

Large Scale ◽

Protein Complexes ◽

The Other ◽

Blood Samples

In recent months a bumper crop of genomes has been completed, including the fission yeast (Schizosaccharomyces pombe) and rice (Oryza sativa). Two large-scale studies ofSaccharomyces cerevisiaeprotein complexes provided a picture of the eukaryotic proteome as a network of complexes. Amongst the other stories of interest was a demonstration that proteomic analysis of blood samples can be used to detect ovarian cancer, perhaps even as early as stage I.

Download Full-text