A new phosphate-starvation response in fission yeast requires the endocytic function of myosin I
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ABSTRACT:
ORGANISM(S): Schizosaccharomyces pombe
PROVIDER: GSE67126 | GEO | 2015/09/15
SECONDARY ACCESSION(S): PRJNA279001
REPOSITORIES: GEO
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Project description:Endocytosis is essential for uptake of many substances into the cell, but how it links to nutritional signalling is poorly understood. Here, we show a new role for endocytosis in regulating the response to low phosphate in Schizosaccharomyces pombe. Loss of function of myosin I (Myo1), Sla2/End4 or Arp2, proteins involved in the early steps of endocytosis, led to increased proliferation in low-phosphate medium compared to controls. We show that once cells are deprived of phosphate they undergo a quiescence response that is dependent on the endocytic function of Myo1. Transcriptomic analysis revealed a wide perturbation of gene expression with induction of stress-regulated genes upon phosphate starvation in wild-type but not ?myo1 cells. Thus, endocytosis plays a pivotal role in mediating the cellular response to nutrients, bridging the external environment and internal molecular functions of the cell.
| S-EPMC4631780 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2015-09-15 | E-GEOD-67126 | biostudies-arrayexpress
Project description:S. pombe Myosin I (MyoI) plays a key role in cytoskeletal functions, in particular it is part of the endocytotic machinery. Here we show a novel role for MyoI in regulating the response to low phosphate stress. Deletion of MyoI led to an increased proliferation in low phosphate media when compared to a control strain; mutations in other proteins involved in the early steps of endocytosis, such as ARP2 and Sla2/END4, led to the same phenotype. We show that once cells are deprived of phosphate they undergo clear morphological changes, slow down growth but retain viability. This is reminiscent of a quiescence response, and it is completely abolished when MyoI is absent. Transcriptomic analysis revealed a wide perturbation of gene expression upon phosphate starvation, with rapid induction of stress-regulated genes. However, Æmyo1 cells displayed little or negligible effects at gene expression level when they were phosphate-starved. Using a combination of super resolution microscopy and genetic approaches we pinpointed the specific function of MyoI in endocytosis as critical for the response to low phosphate stress. Furthermore, introduction of point-mutated MyoI (with ablated endocytic function) into a ÆmyoI background failed to restore phosphate stress response. Taken together, our data indicate how endocytosis, and in particular MyoI, play a pivotal role in mediating cellular response to nutrients, bridging the external environment and internal molecular functions of the cells.
2015-09-15 | GSE67105 | GEO
Project description:S. pombe Myosin I (MyoI) plays a key role in cytoskeletal functions, in particular it is part of the endocytotic machinery. Here we show a novel role for MyoI in regulating the response to low phosphate stress. Deletion of MyoI led to an increased proliferation in low phosphate media when compared to a control strain; mutations in other proteins involved in the early steps of endocytosis, such as ARP2 and Sla2/END4, led to the same phenotype. We show that once cells are deprived of phosphate they undergo clear morphological changes, slow down growth but retain viability. This is reminiscent of a quiescence response, and it is completely abolished when MyoI is absent. Transcriptomic analysis revealed a wide perturbation of gene expression upon phosphate starvation, with rapid induction of stress-regulated genes. However, Æmyo1 cells displayed little or negligible effects at gene expression level when they were phosphate-starved. Using a combination of super resolution microscopy and genetic approaches we pinpointed the specific function of MyoI in endocytosis as critical for the response to low phosphate stress. Furthermore, introduction of point-mutated MyoI (with ablated endocytic function) into a ÆmyoI background failed to restore phosphate stress response. Taken together, our data indicate how endocytosis, and in particular MyoI, play a pivotal role in mediating cellular response to nutrients, bridging the external environment and internal molecular functions of the cells.
2015-09-15 | GSE65579 | GEO
Project description:S. pombe Myosin I (MyoI) plays a key role in cytoskeletal functions, in particular it is part of the endocytotic machinery. Here we show a novel role for MyoI in regulating the response to low phosphate stress. Deletion of MyoI led to an increased proliferation in low phosphate media when compared to a control strain; mutations in other proteins involved in the early steps of endocytosis, such as ARP2 and Sla2/END4, led to the same phenotype. We show that once cells are deprived of phosphate they undergo clear morphological changes, slow down growth but retain viability. This is reminiscent of a quiescence response, and it is completely abolished when MyoI is absent. Transcriptomic analysis revealed a wide perturbation of gene expression upon phosphate starvation, with rapid induction of stress-regulated genes. However, Æmyo1 cells displayed little or negligible effects at gene expression level when they were phosphate-starved. Using a combination of super resolution microscopy and genetic approaches we pinpointed the specific function of MyoI in endocytosis as critical for the response to low phosphate stress. Furthermore, introduction of point-mutated MyoI (with ablated endocytic function) into a ÆmyoI background failed to restore phosphate stress response. Taken together, our data indicate how endocytosis, and in particular MyoI, play a pivotal role in mediating cellular response to nutrients, bridging the external environment and internal molecular functions of the cells. ChIP-seq analysis of Myo1-GFP genomic binding in control or low phosphate condition
2015-09-15 | E-GEOD-67105 | biostudies-arrayexpress
Project description:S. pombe Myosin I (MyoI) plays a key role in cytoskeletal functions, in particular it is part of the endocytotic machinery. Here we show a novel role for MyoI in regulating the response to low phosphate stress. Deletion of MyoI led to an increased proliferation in low phosphate media when compared to a control strain; mutations in other proteins involved in the early steps of endocytosis, such as ARP2 and Sla2/END4, led to the same phenotype. We show that once cells are deprived of phosphate they undergo clear morphological changes, slow down growth but retain viability. This is reminiscent of a quiescence response, and it is completely abolished when MyoI is absent. Transcriptomic analysis revealed a wide perturbation of gene expression upon phosphate starvation, with rapid induction of stress-regulated genes. However, Æmyo1 cells displayed little or negligible effects at gene expression level when they were phosphate-starved. Using a combination of super resolution microscopy and genetic approaches we pinpointed the specific function of MyoI in endocytosis as critical for the response to low phosphate stress. Furthermore, introduction of point-mutated MyoI (with ablated endocytic function) into a ÆmyoI background failed to restore phosphate stress response. Taken together, our data indicate how endocytosis, and in particular MyoI, play a pivotal role in mediating cellular response to nutrients, bridging the external environment and internal molecular functions of the cells. RNA-seq transcriptomic analysis in control and ∆myo1 S.pombe strains comparing gene expression profiles at 4 and 10 hours after phosphate depletion.
2015-09-15 | E-GEOD-65579 | biostudies-arrayexpress
Project description:Inorganic phosphate is an essential nutrient acquired by cells from their environment and assimilated into myriad intracellular metabolites and macromolecules. Here we characterize the metabolic responses of fission yeast to a 24-h interval of phosphate starvation, during which cells enter a state of G0 quiescence. Time-resolved profiling revealed that many key phosphometabolites were progressively depleted, including: (i) NTPs, NDPs, and dNTPs; (ii) coenzyme A, NAD+, NADP+, NADH, and ADP-ribose; (iii) glycolysis pathway intermediates upstream of pyruvate; (iv) pentose phosphate pathway intermediates from 6-phosphogluconate to sedoheptulose-7-phosphate; (v) nucleotide sugars GDP-glucose/mannose, UDP-glucose/galactose, and UDP-GalNAc/GluNAc; and (vi) phospholipid precursors glycerol-3-phosphate, CDP-choline, and glycerophosphocholine. By contrast, early Krebs cycle intermediates accumulated during phosphate starvation. Other metabolic changes included: (i) interdiction of de novo pyrimidine synthesis; (ii) depletion of S-adenosylmethionine and S-adenosylhomocysteine; (iii) transient accumulation of polyamine biosynthetic intermediates putrescine, S-adenosylmethioninamine and 5-methylthioadenosine; (iv) accumulation of betaine (correlating with an increase in expression of atd1 mRNA encoding aldehyde dehydrogenase); and (v) depletion of aminoadipate pathway intermediates 2-oxoadipate, 2-aminoadipate and saccharopine. Replenishing phosphate after 24 h of starvation resulted in restoration of the metabolite levels to similar levels as non-starved controls (over 2 to 12 h) as cells exited quiescence and resumed growth.
2024-12-17 | MSV000096678 | MassIVE
Project description:We used the dendritic nucleation hypothesis to formulate a mathematical model of the assembly and disassembly of actin filaments at sites of clathrin-mediated endocytosis in fission yeast. We used the wave of active WASp recruitment at the site of the patch formation to drive assembly reactions after activation of Arp2/3 complex. Capping terminated actin filament elongation. Aging of the filaments by ATP hydrolysis and gamma-phosphate dissociation allowed actin filament severing by cofilin. The model could simulate the assembly and disassembly of actin and other actin patch proteins using measured cytoplasmic concentrations of the proteins. However, to account quantitatively for the numbers of proteins measured over time in the accompanying article (Sirotkin et al., 2010, MBoC 21: 2792-2802), two reactions must be faster in cells than in vitro. Conditions inside the cell allow capping protein to bind to the barbed ends of actin filaments and Arp2/3 complex to bind to the sides of filaments faster than the purified proteins in vitro. Simulations also show that depolymerization from pointed ends cannot account for rapid loss of actin filaments from patches in 10 s. An alternative mechanism consistent with the data is that severing produces short fragments that diffuse away from the patch.
| S-EPMC2921120 | biostudies-literature
Project description:Eukaryotic cells adapt their metabolism to the extracellular environment. Downregulation of surface cargo proteins in response to nutrient stress reduces the burden of anabolic processes whilst elevating catabolic production in the lysosome. We show that glucose starvation in yeast triggers a transcriptional response that increases internalisation from the plasma membrane. Nuclear export of the Mig1 transcriptional repressor in response to glucose starvation increases levels of the Yap1801 and Yap1802 clathrin adaptors, which is sufficient to increase cargo internalisation. Beyond this, we show that glucose starvation results in Mig1-independent transcriptional upregulation of various eisosomal factors. These factors serve to sequester a portion of nutrient transporters at existing eisosomes, through the presence of Ygr130c and biochemical and biophysical changes in Pil1, allowing cells to persist throughout the starvation period and maximise nutrient uptake upon return to replete conditions. This provides a physiological benefit for cells to rapidly recover from glucose starvation. Collectively, this remodelling of the surface protein landscape during glucose starvation calibrates metabolism to available nutrients.This article has an associated First Person interview with the first author of the paper.
| S-EPMC7860119 | biostudies-literature
Project description:Myosin V motors are believed to contribute to cell polarization by carrying cargoes along actin tracks. In Schizosaccharomyces pombe, Myosin Vs transport secretory vesicles along actin cables, which are dynamic actin bundles assembled by the formin For3 at cell poles. How these flexible structures are able to extend longitudinally in the cell through the dense cytoplasm is unknown. Here we show that in myosin V (myo52 myo51) null cells, actin cables are curled, bundled, and fail to extend into the cell interior. They also exhibit reduced retrograde flow, suggesting that formin-mediated actin assembly is impaired. Myo52 may contribute to actin cable organization by delivering actin regulators to cell poles, as myoV defects are partially suppressed by diverting cargoes toward cell tips onto microtubules with a kinesin 7-Myo52 tail chimera. In addition, Myo52 motor activity may pull on cables to provide the tension necessary for their extension and efficient assembly, as artificially tethering actin cables to the nuclear envelope via a Myo52 motor domain restores actin cable extension and retrograde flow in myoV mutants. Together these in vivo data reveal elements of a self-organizing system in which the motors shape their own tracks by transporting cargoes and exerting physical pulling forces.
| S-EPMC3510019 | biostudies-literature