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Li X, Yang C, Wu H, Chen H, Gao X, Zhou S, Zhang TC, Ma W. DSB-induced oxidative stress: Uncovering crosstalk between DNA damage response and cellular metabolism. DNA Repair (Amst) 2024; 141:103730. [PMID: 39018963 DOI: 10.1016/j.dnarep.2024.103730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 06/21/2024] [Accepted: 07/12/2024] [Indexed: 07/19/2024]
Abstract
While that ROS causes DNA damage is well documented, there has been limited investigation into whether DNA damages and their repair processes can conversely induce oxidative stress. By generating a site-specific DNA double strand break (DSB) via I-SceI endonuclease expression in S. cerevisiae without damaging other cellular components, this study demonstrated that DNA repair does trigger oxidative stress. Deleting genes participating in the initiation of the resection step of homologous recombination (HR), like the MRX complex, resulted in stimulation of ROS. In contrast, deleting genes acting downstream of HR resection suppressed ROS levels. Additionally, blocking non-homologous end joining (NHEJ) also suppressed ROS. Further analysis identified Rad53 as a key player that relays DNA damage signals to alter redox metabolism in an HR-specific manner. These results suggest both HR and NHEJ can drive metabolism changes and oxidative stress, with NHEJ playing a more prominent role in ROS stimulation. Further analysis revealed a correlation between DSB-induced ROS increase and enhanced activity of NADPH oxidase Yno1 and various antioxidant enzymes. Deleting the antioxidant gene SOD1 induced synthetic lethality in HR-deficient mutants like mre11Δ and rad51Δ upon DSB induction. These findings uncover a significant interplay between DNA repair mechanisms and cellular metabolism, providing insights into understanding the side effects of genotoxic therapies and potentially aiding development of more effective cancer treatment strategies.
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Affiliation(s)
- Xinyu Li
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Caini Yang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Hengyu Wu
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Hongran Chen
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Xing Gao
- Qilu Institute of Technology, Shandong, China
| | - Sa Zhou
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China.
| | - Tong-Cun Zhang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China; Institute of Biology and Medicine, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Wenjian Ma
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China; Qilu Institute of Technology, Shandong, China.
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2
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Tan EW, Abdullah ADI, Ming LC, Poh CL, Goh BH, Lau TP, Tan KO. Adenovirus-mediated expression of MOAP-1, Bax and RASSF1A antagonizes chemo-drug resistance of human breast cancer cells expressing cancer stem cell markers. Biomed Pharmacother 2024; 176:116744. [PMID: 38810399 DOI: 10.1016/j.biopha.2024.116744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 05/06/2024] [Accepted: 05/09/2024] [Indexed: 05/31/2024] Open
Abstract
Cancer is one of the major leading causes of mortality globally and chemo-drug-resistant cancers pose significant challenges to cancer treatment by reducing patient survival rates and increasing treatment costs. Although the mechanisms of chemoresistance vary among different types of cancer, cancer cells are known to share several hallmarks, such as their resistance to apoptosis as well as the ability of cancer stem cells to produce metastatic daughter cells that are resistant to chemotherapy. To address the issue of chemo-drug resistance in cancer cells, a tetracistronic expression construct, Ad-MBR-GFP, encoding adenovirus-mediated expression of MOAP-1, Bax, RASSSF1A, and GFP, was generated to investigate its potential activity in reducing or inhibiting the chemo-drug resistant activity of the human breast cancer cells, MCF-7-CR and MDA-MB-231. When infected by Ad-MBR-GFP, the cancer cells exhibited round cell morphology and nuclei condensation with positive staining for annexin-V. Furthermore, our results showed that both MCF-7-CR and MDA-MB-231 cells stained positively for CD 44 and negatively for CD 24 (CD44+/CD24-) with high levels of endogenous ALDH activity whereas SNU-1581 breast cancer cells were identified as CD 44-/CD 24- cells with relatively low levels of endogenous ALDH activity and high sensitivity toward chemo-drugs, suggesting that both CD 44 and ALDH activity contribute to chemo-drug resistance. Moreover, both MCF-7-CR and MDA-MB-231 cells showed strong chemo-drug sensitivity to cisplatin when the cells were infected by Ad-MBR-GFP, leading to 9-fold and 2-fold reduction in the IC 50 values when compared to cisplatin treatment alone, respectively. The data were further supported by 3D (soft agar) and spheroid cell models of MCF-7-CR and MDA-MB-231 cells which showed a 2-fold reduction of a number of cell colonies and spheroid size when treated with both Ad-MBR-GFP and cisplatin, and compared to control. Other than chemo-sensitivity, Ad-MBR-GFP-infected cancer cells retarded cell migration. Flow cytometry analysis showed that the mechanism of action of Ad-MBR-GFP involved cell cycle arrest at the G1 phase and inhibition of cellular DNA synthesis. Taken together, our investigation showed that Ad-MBR-GFP mediated chemo-drug sensitization in the infected cancer cells involved the activation of apoptosis signaling, cell cycle arrest, and inhibition of DNA synthesis, suggesting that Ad-MBR-GFP is potentially efficacious for the treatment of chemo-drug resistant cancers.
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Affiliation(s)
- Ee Wern Tan
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Sunway City 47500, Malaysia; Sunway Biofunctional Molecules Discovery Centre, School of Medical and Life Sciences, Sunway University, Sunway City 47500, Malaysia
| | - Amar Daud Iskandar Abdullah
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Sunway City 47500, Malaysia
| | - Long Chiau Ming
- Department of Medical Sciences, School of Medical and Life Sciences, Sunway University, Sunway City 47500, Malaysia
| | - Chit Laa Poh
- Centre for Virus and Vaccine Research, School of Medical and Life Sciences, Sunway University, Sunway City 47500, Malaysia
| | - Bey Hing Goh
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Sunway City 47500, Malaysia; Sunway Biofunctional Molecules Discovery Centre, School of Medical and Life Sciences, Sunway University, Sunway City 47500, Malaysia; Faculty of Health, Australian Research Centre in Complementary and Integrative Medicine, University of Technology Sydney, Ultimo 2007, NSW, Australia
| | - Tze Pheng Lau
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Sunway City 47500, Malaysia.
| | - Kuan Onn Tan
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Sunway City 47500, Malaysia.
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3
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Hildebrandt ER, Hussain SA, Sieburg MA, Ravishankar R, Asad N, Gore S, Ito T, Hougland JL, Dore TM, Schmidt WK. Targeted genetic and small molecule disruption of N-Ras CaaX cleavage alters its localization and oncogenic potential. Bioorg Chem 2024; 147:107316. [PMID: 38583246 PMCID: PMC11098683 DOI: 10.1016/j.bioorg.2024.107316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/16/2024] [Accepted: 03/26/2024] [Indexed: 04/09/2024]
Abstract
Ras GTPases and other CaaX proteins undergo multiple post-translational modifications at their carboxyl-terminus. These events initiate with prenylation of a cysteine and are followed by endoproteolytic removal of the 'aaX' tripeptide and carboxylmethylation. Some CaaX proteins are only subject to prenylation, however, due to the presence of an uncleavable sequence. In this study, uncleavable sequences were used to stage Ras isoforms in a farnesylated and uncleaved state to address the impact of CaaX proteolysis on protein localization and function. This targeted strategy is more specific than those that chemically inhibit the Rce1 CaaX protease or delete the RCE1 gene because global abrogation of CaaX proteolysis impacts the entire CaaX protein proteome and effects cannot be attributed to any specific CaaX protein of the many concurrently affected. With this targeted strategy, clear mislocalization and reduced activity of farnesylated and uncleaved Ras isoforms was observed. In addition, new peptidomimetics based on cleavable Ras CaaX sequences and the uncleavable CAHQ sequence were synthesized and tested as Rce1 inhibitors using in vitro and cell-based assays. Consistently, these non-hydrolyzable peptidomimetic Rce1 inhibitors recapitulate Ras mislocalization effects when modeled on cleavable but not uncleavable CaaX sequences. These findings indicate that a prenylated and uncleavable CaaX sequence, which can be easily applied to a wide range of mammalian CaaX proteins, can be used to probe the specific impact of CaaX proteolysis on CaaX protein properties under conditions of an otherwise normally processed CaaX protein proteome.
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Affiliation(s)
- Emily R Hildebrandt
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA
| | - Shaneela A Hussain
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE
| | | | - Rajani Ravishankar
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA
| | - Nadeem Asad
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE
| | - Sangram Gore
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE
| | - Takahiro Ito
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA
| | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY, USA; Department of Biology, Syracuse University, Syracuse, NY, USA; BioInspired Syracuse, Syracuse University, Syracuse, NY, USA
| | - Timothy M Dore
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE; Department of Chemistry, University of Georgia, Athens, GA, USA
| | - Walter K Schmidt
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA.
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Piper-Brown E, Dresel F, Badr E, Gourlay CW. Elevated Levels of Mislocalised, Constitutive Ras Signalling Can Drive Quiescence by Uncoupling Cell-Cycle Regulation from Metabolic Homeostasis. Biomolecules 2023; 13:1619. [PMID: 38002301 PMCID: PMC10669370 DOI: 10.3390/biom13111619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 10/28/2023] [Accepted: 10/30/2023] [Indexed: 11/26/2023] Open
Abstract
The small GTPase Ras plays an important role in connecting external and internal signalling cues to cell fate in eukaryotic cells. As such, the loss of RAS regulation, localisation, or expression level can drive changes in cell behaviour and fate. Post-translational modifications and expression levels are crucial to ensure Ras localisation, regulation, function, and cell fate, exemplified by RAS mutations and gene duplications that are common in many cancers. Here, we reveal that excessive production of yeast Ras2, in which the phosphorylation-regulated serine at position 225 is replaced with alanine or glutamate, leads to its mislocalisation and constitutive activation. Rather than inducing cell death, as has been widely reported to be a consequence of constitutive Ras2 signalling in yeast, the overexpression of RAS2S225A or RAS2S225E alleles leads to slow growth, a loss of respiration, reduced stress response, and a state of quiescence. These effects are mediated via cAMP/PKA signalling and transcriptional changes, suggesting that quiescence is promoted by an uncoupling of cell-cycle regulation from metabolic homeostasis. The quiescent cell fate induced by the overexpression of RAS2S225A or RAS2S225E could be rescued by the deletion of CUP9, a suppressor of the dipeptide transporter Ptr2, or the addition of peptone, implying that a loss of metabolic control, or a failure to pass a metabolic checkpoint, is central to this altered cell fate. Our data suggest that the combination of an increased RAS2 copy number and a dominant active mutation that leads to its mislocalisation can result in growth arrest and add weight to the possibility that approaches to retarget RAS signalling could be employed to develop new therapies.
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Affiliation(s)
| | | | | | - Campbell W. Gourlay
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NZ, UK
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5
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Yeast cell death pathway requiring AP-3 vesicle trafficking leads to vacuole/lysosome membrane permeabilization. Cell Rep 2022; 39:110647. [PMID: 35417721 PMCID: PMC9074372 DOI: 10.1016/j.celrep.2022.110647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 02/17/2022] [Accepted: 03/16/2022] [Indexed: 12/24/2022] Open
Abstract
Unicellular eukaryotes have been suggested as undergoing self-inflicted destruction. However, molecular details are sparse compared with the mechanisms of programmed/regulated cell death known for human cells and animal models. Here, we report a molecular cell death pathway in Saccharomyces cerevisiae leading to vacuole/lysosome membrane permeabilization. Following a transient cell death stimulus, yeast cells die slowly over several hours, consistent with an ongoing molecular dying process. A genome-wide screen for death-promoting factors identified all subunits of the AP-3 complex, a vesicle trafficking adapter known to transport and install newly synthesized proteins on the vacuole/lysosome membrane. To promote cell death, AP-3 requires its Arf1-GTPase-dependent vesicle trafficking function and the kinase Yck3, which is selectively transported to the vacuole membrane by AP-3. Video microscopy revealed a sequence of events where vacuole permeability precedes the loss of plasma membrane integrity. AP-3-dependent death appears to be conserved in the human pathogenic yeast Cryptococcus neoformans. Details about how mammalian cells die have yielded effective cancer therapies. Similarly, details about fungal cell death may explain failed responses to anti-fungal agents and inform next-generation anti-fungal strategies. Stolp et al. describe a potential mechanism of yeast cell death subversion, by inhibiting AP-3 vesicle trafficking to block vacuole/lysosome permeability.
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6
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Kumpakha R, Gordon DM. Inhibition of morphological transition and hyphae extension in Candida spp. by occidiofungin. J Appl Microbiol 2021; 132:3038-3048. [PMID: 34941005 DOI: 10.1111/jam.15425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 12/05/2021] [Accepted: 12/20/2021] [Indexed: 11/28/2022]
Abstract
AIMS To assess the efficacy of the antifungal, occidiofungin, against Candida albicans and Candida tropicalis morphological transformation. METHODS AND RESULTS Susceptibility assays and morphological data were used to demonstrate that occidiofungin effectively targets C. albicans and C. tropicalis undergoing morphological transformation. Susceptibility assays found that cell sensitivity to occidiofungin varied with the media conditions used for morphological switching. Microscopy data showed that occidiofungin inhibited hyphae formation when added at the time of morphological induction and hyphal extension when added within the first hour following hyphae induction. Immunoblot analysis demonstrated that occidiofungin addition prevented activation of Cek1p MAPK signalling. CONCLUSIONS The data indicated that the antimicrobial compound, occidiofungin, effectively targets hyphae elongation in Candida spp. and suggests the biological target of occidiofungin is necessary for the morphological changes associated with yeast-to-hyphae switching. SIGNIFICANCE AND IMPACT OF THE STUDY Findings from this study demonstrated that occidiofungin effectively targets the invasive growth of dimorphic Candida which suggests this compound may also inhibit the heterogenous population of cells present in a clinical setting. This presents occidiofungin as a promising candidate for the treatment of Candida associated infections.
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Affiliation(s)
- Rabina Kumpakha
- Department of Biological Sciences, Mississippi State University, Mississippi State, Mississippi, USA
| | - Donna M Gordon
- Department of Biological Sciences, Mississippi State University, Mississippi State, Mississippi, USA
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7
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Salas-Navarrete PC, de Oca Miranda AIM, Martínez A, Caspeta L. Evolutionary and reverse engineering to increase Saccharomyces cerevisiae tolerance to acetic acid, acidic pH, and high temperature. Appl Microbiol Biotechnol 2021; 106:383-399. [PMID: 34913993 DOI: 10.1007/s00253-021-11730-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 12/01/2021] [Accepted: 12/03/2021] [Indexed: 11/24/2022]
Abstract
Saccharomyces cerevisiae scarcely grows on minimal media with acetic acid, acidic pH, and high temperatures. In this study, the adaptive laboratory evolution (ALE), whole-genome analysis, and reverse engineering approaches were used to generate strains tolerant to these conditions. The thermotolerant strain TTY23 and its parental S288C were evolved through 1 year, in increasing concentrations of acetic acid up to 12 g/L, keeping the pH ≤ 4. Of the 18 isolated strains, 9 from each ancestor, we selected the thermo-acid tolerant TAT12, derived from TTY23, and the acid tolerant AT22, derived from S288C. Both grew in minimal media with 12 g/L of acetic acid, pH 4, and 30 °C, and produced ethanol up to 29.25 ± 6 mmol/gDCW/h-neither of the ancestors thrived in these conditions. Furthermore, only the TAT12 grew on 2 g/L of acetic acid, pH 3, and 37 °C, and accumulated 16.5 ± 0.5 mmol/gDCW/h of ethanol. Whole-genome sequencing and transcriptomic analysis of this strain showed changes in the genetic sequence and transcription of key genes involved in the RAS-cAMP-PKA signaling pathway (RAS2, GPA2, and IRA2), the heat shock transcription factor (HSF1), and the positive regulator of replication initiation (SUM1), among others. By reverse engineering, the relevance of the combined mutations in the genes RAS2, HSF1, and SUM1 to the tolerance for acetic acid, low pH, and high temperature was confirmed. Alone, the RAS2 mutation yielded acid tolerance and HSF1 nutation thermotolerance. Increasing the thermo-acidic niche and acetic acid tolerance of S. cerevisiae can contribute to improve economic ethanol production. KEY POINTS: • Thermo-acid tolerant (TAT) yeast strains were generated by adaptive laboratory evolution. • The strain TAT12 thrived on non-native, thermo-acidic harmful conditions. • Mutations in RAS2, HSF1, and SUM1 genes rendered yeast thermo and acid tolerant.
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Affiliation(s)
- Prisciluis Caheri Salas-Navarrete
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, C.P. 62209, Cuernavaca, Morelos, Mexico
| | - Arturo Iván Montes de Oca Miranda
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, C.P. 62209, Cuernavaca, Morelos, Mexico
| | - Alfredo Martínez
- Departamento de Ingeniería Celular Y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, C.P. 62210, Cuernavaca, Morelos, Mexico
| | - Luis Caspeta
- Departamento de Ingeniería Celular Y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, C.P. 62210, Cuernavaca, Morelos, Mexico.
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8
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Sellers-Moya Á, Nuévalos M, Molina M, Martín H. Clotrimazole-Induced Oxidative Stress Triggers Novel Yeast Pkc1-Independent Cell Wall Integrity MAPK Pathway Circuitry. J Fungi (Basel) 2021; 7:jof7080647. [PMID: 34436186 PMCID: PMC8399625 DOI: 10.3390/jof7080647] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/03/2021] [Accepted: 08/05/2021] [Indexed: 01/13/2023] Open
Abstract
Azoles are one of the most widely used drugs to treat fungal infections. To further understand the fungal response to azoles, we analyzed the MAPK circuitry of the model yeast Saccharomyces cerevisiae that operates under treatment with these antifungals. Imidazoles, and particularly clotrimazole, trigger deeper changes in MAPK phosphorylation than triazoles, involving a reduction in signaling through the mating pathway and the activation of the MAPKs Hog1 and Slt2 from the High-Osmolarity Glycerol (HOG) and the Cell Wall Integrity (CWI) pathways, respectively. Clotrimazole treatment leads to actin aggregation, mitochondrial alteration, and oxidative stress, which is essential not only for the activation of both MAPKs, but also for the appearance of a low-mobility form of Slt2 caused by additional phosphorylation to that occurring at the conserved TEY activation motif. Clotrimazole-induced ROS production and Slt2 phosphorylation are linked to Tpk3-mediated PKA activity. Resistance to clotrimazole depends on HOG and CWI-pathway-mediated stress responses. However, Pkc1 and other proteins acting upstream in the pathway are not critical for the activation of the Slt2 MAPK module, suggesting a novel rewiring of signaling through the CWI pathway. We further show that the strong impact of azole treatment on MAPK signaling is conserved in other yeast species.
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Affiliation(s)
| | | | - María Molina
- Correspondence: (M.M.); (H.M.); Tel.: +34-91-3941888 (M.M. & H.M.)
| | - Humberto Martín
- Correspondence: (M.M.); (H.M.); Tel.: +34-91-3941888 (M.M. & H.M.)
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9
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Ras2 is important for growth and pathogenicity in Fusarium circinatum. Fungal Genet Biol 2021; 150:103541. [PMID: 33639303 DOI: 10.1016/j.fgb.2021.103541] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 11/21/2022]
Abstract
In this study, we investigated to possible role of Ras2 in Fusarium circinatum- a fungus that causes pine pitch canker disease on many different pine species and has a wide geographic distribution. This protein is encoded by the RAS2 gene and has been shown to control growth and pathogenicity in a number of fungi in a mitogen-activated protein kinase- and/or cyclic adenosyl monophosphate pathway-dependent manner. The aim was therefore to characterize the phenotypes of RAS2 gene knockout and complementation mutants of F. circinatum. These mutants were generated by transforming protoplasts of the fungus with suitable split-marker constructs. The mutant strains, together with the wild type strain, were used in growth studies as well as pathogenicity assays on Pinus patula seedlings. Results showed that the knockout mutant strain produced significantly smaller lesions compared to the complementation mutant and wild type strains. Growth studies also showed significantly smaller colonies and delayed conidial germination in the knockout mutant strain compared to the complement mutant and wild type strains. Interestingly, the knockout mutant strain produced more macroconidia than the wild type strain. Collectively, these results showed that Ras2 plays an important role in both growth and pathogenicity of F. circinatum. Future studies will seek to determine the pathway(s) through which Ras2 controls these traits in F. circinatum.
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10
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Somboon P, Soontorngun N. An actin depolymerizing agent 19,20-epoxycytochalasin Q of Xylaria sp. BCC 1067 enhanced antifungal action of azole drugs through ROS-mediated cell death in yeast. Microbiol Res 2020; 243:126646. [PMID: 33227681 DOI: 10.1016/j.micres.2020.126646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 10/30/2020] [Accepted: 11/06/2020] [Indexed: 01/21/2023]
Abstract
Multidrug resistance is a highly conserved phenomenon among all living organisms and a major veritable public health problem worldwide. Repetitive uses of antibiotics lead to antimicrobial drug resistance. Here, 19,20-epoxycytochalasin Q (ECQ) was isolated from endophytic fungus Xylaria sp. BCC 1067 and, its chemical structure was determined via chromatographic and spectral methods. ECQ displayed an antifungal activity with low MIC50 of 410 and 55 mg/l in the model yeast Saccharomyces cerevisiae wild-type and ScΔpdr5 strains, respectively. ECQ was a new inducer and potential substrate of key multi-drug efflux pumps S. cerevisiae ScPdr5 and Candida albicans CaCdr1. ECQ targeted actin filament, disrupting actin dynamics of yeast cells. ECQ also sensitized the ScΔsrv2 mutant, lacking suppressor of RasVal19. Overexpression of ScPDR5 or CaCDR1 genes prevented aggregation of actin and alleviated antifungal effect of ECQ. Additionally, ECQ induced high accumulation of reactive oxygen species, caused plasma membrane leakage and decreased yeast cell survival. Importantly, a discovery of ECQ implied a cellular connection between multi-drug resistance and actin stability, an important determinant of transporter mediated-drug resistance mechanism. Combination of ECQ and antifungal azoles displayed promising drug synergy against S. cerevisiae strains expressing multi-drug transporters, thereby providing potential solution for antifungal therapy and chemotherapeutic application.
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Affiliation(s)
- Pichayada Somboon
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Nitnipa Soontorngun
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand.
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11
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Manohar S, Camacho-Magallanes A, Echeverria C, Rogers CD. Cadherin-11 Is Required for Neural Crest Specification and Survival. Front Physiol 2020; 11:563372. [PMID: 33192560 PMCID: PMC7662130 DOI: 10.3389/fphys.2020.563372] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 10/06/2020] [Indexed: 01/06/2023] Open
Abstract
Neural crest (NC) cells are multipotent embryonic cells that form melanocytes, craniofacial bone and cartilage, and the peripheral nervous system in vertebrates. NC cells express many cadherin proteins, which control their specification, epithelial to mesenchymal transition (EMT), migration, and mesenchymal to epithelial transition. Abnormal NC development leads to congenital defects including craniofacial clefts as well as NC-derived cancers. Here, we identify the role of the type II cadherin protein, Cadherin-11 (CDH11), in early chicken NC development. CDH11 is known to play a role in NC cell migration in amphibian embryos as well as cell survival, proliferation, and migration in cancer cells. It has also been linked to the complex neurocristopathy disorder, Elsahy-Waters Syndrome, in humans. In this study, we knocked down CDH11 translation at the onset of its expression in the NC domain during NC induction. Loss of CDH11 led to a reduction of bonafide NC cells in the dorsal neural tube combined with defects in cell survival and migration. Loss of CDH11 increased p53-mediated programmed-cell death, and blocking the p53 pathway rescued the NC phenotype. Our findings reveal an early requirement for CDH11 in NC development and demonstrated the complexity of the mechanisms that regulate NC development, where a single cell-cell adhesion protein simultaneous controls multiple essential cellular functions to ensure proper specification, survival, and transition to a migratory phase in the dorsal neural tube. Our findings may also increase our understanding of early cadherin-related NC developmental defects.
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Affiliation(s)
- Subrajaa Manohar
- Department of Biology, School of Math and Science, California State University Northridge, Northridge, CA, United States
| | - Alberto Camacho-Magallanes
- Department of Biology, School of Math and Science, California State University Northridge, Northridge, CA, United States
| | - Camilo Echeverria
- Department of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, Davis, CA, United States
| | - Crystal D Rogers
- Department of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, Davis, CA, United States
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12
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Akintade DD, Chaudhuri B. Apoptosis, Induced by Human α-Synuclein in Yeast, Can Occur Independent of Functional Mitochondria. Cells 2020; 9:cells9102203. [PMID: 33003464 PMCID: PMC7601298 DOI: 10.3390/cells9102203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 12/16/2022] Open
Abstract
Human α-synuclein expression in baker’s yeast reportedly induces mitochondria-dependent apoptosis. Surprisingly, we find that, under de-repressing conditions of the inducible MET25/GAL1 promoters, yeast cells expressing chromosomally-integrated copies of the human α-synuclein gene are not killed, but spontaneously form respiration-deficient rho-minus (ρ−) petites. Although yeast cells can undergo cell death (apoptosis) from loss of mitochondrial function, they can also survive without functional mitochondria. Such cells are referred to as ρ0 or ρ− petites. This study reports that minimal expression of human α-synuclein in yeast, from MET25/GAL1 promoter, gives rise to ρ− petites. Interestingly, the full expression of α-synuclein, from the same promoters, in α-synuclein-triggered ρ− petites and also in ρ0 petites (produced by treating ρ+ cells with the mutagen ethidium bromide) initiates apoptosis. The percentages of petites increase with increasing α-synuclein gene copy-number. ρ− petites expressing α-synuclein from fully-induced MET25/GAL1 promoters exhibit increased ROS levels, loss of mitochondrial membrane potential, and nuclear DNA fragmentation, with increasing copies of α-synuclein. Our results indicate that, for the first time in yeast, α-synuclein-triggered apoptosis can occur independently of functional mitochondria. The observation that α-synuclein naturally forms petites and that they can undergo apoptosis may have important implications in understanding the pathogenesis of Parkinson’s disease.
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Affiliation(s)
- Damilare D. Akintade
- School of Life Sciences, Medical School, University of Nottingham, Nottingham NG7 2UH, UK
- Leicester School of Pharmacy, De Montfort University, Leicester LE1 9BH, UK;
- Correspondence: ; Tel.: +44-07712452922
| | - Bhabatosh Chaudhuri
- Leicester School of Pharmacy, De Montfort University, Leicester LE1 9BH, UK;
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13
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Proteomic analysis revealed ROS-mediated growth inhibition of Aspergillus terreus by shikonin. J Proteomics 2020; 224:103849. [DOI: 10.1016/j.jprot.2020.103849] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 02/17/2020] [Accepted: 05/26/2020] [Indexed: 12/19/2022]
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14
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Gibney PA, Chen A, Schieler A, Chen JC, Xu Y, Hendrickson DG, McIsaac RS, Rabinowitz JD, Botstein D. A tps1Δ persister-like state in Saccharomyces cerevisiae is regulated by MKT1. PLoS One 2020; 15:e0233779. [PMID: 32470059 PMCID: PMC7259636 DOI: 10.1371/journal.pone.0233779] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 05/12/2020] [Indexed: 11/18/2022] Open
Abstract
Trehalose metabolism in yeast has been linked to a variety of phenotypes, including heat resistance, desiccation tolerance, carbon-source utilization, and sporulation. The relationships among the several phenotypes of mutants unable to synthesize trehalose are not understood, even though the pathway is highly conserved. One of these phenotypes is that tps1Δ strains cannot reportedly grow on media containing glucose or fructose, even when another carbon source they can use (e.g. galactose) is present. Here we corroborate the recent observation that a small fraction of yeast tps1Δ cells do grow on glucose, unlike the majority of the population. This is not due to a genetic alteration, but instead resembles the persister phenotype documented in many microorganisms and cancer cells undergoing lethal stress. We extend these observations to show that this phenomenon is glucose-specific, as it does not occur on another highly fermented carbon source, fructose. We further demonstrate that this phenomenon appears to be related to mitochondrial complex III function, but unrelated to inorganic phosphate levels in the cell, as had previously been suggested. Finally, we found that this phenomenon is specific to S288C-derived strains, and is the consequence of a variant in the MKT1 gene.
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Affiliation(s)
- Patrick A. Gibney
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Calico Life Sciences LLC, South San Francisco, California, United States of America
- Department of Food Science, Cornell University, Ithaca, New York, United States of America
| | - Anqi Chen
- Department of Food Science, Cornell University, Ithaca, New York, United States of America
| | - Ariel Schieler
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Jonathan C. Chen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Chemistry, Princeton University, Princeton, New Jersey, United States of America
| | - Yifan Xu
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Chemistry, Princeton University, Princeton, New Jersey, United States of America
| | - David G. Hendrickson
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - R. Scott McIsaac
- Calico Life Sciences LLC, South San Francisco, California, United States of America
| | - Joshua D. Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Chemistry, Princeton University, Princeton, New Jersey, United States of America
| | - David Botstein
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Calico Life Sciences LLC, South San Francisco, California, United States of America
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15
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Nanosecond duration pulsed electric field together with formic acid triggers caspase-dependent apoptosis in pathogenic yeasts. Bioelectrochemistry 2019; 128:148-154. [DOI: 10.1016/j.bioelechem.2019.04.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 04/08/2019] [Accepted: 04/08/2019] [Indexed: 01/13/2023]
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16
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Ruete MC, Zarelli VEP, Masone D, de Paola M, Bustos DM, Tomes CN. A connection between reversible tyrosine phosphorylation and SNARE complex disassembly activity of N-ethylmaleimide-sensitive factor unveiled by the phosphomimetic mutant N-ethylmaleimide-sensitive factor-Y83E. ACTA ACUST UNITED AC 2019; 25:344-358. [DOI: 10.1093/molehr/gaz031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/16/2019] [Accepted: 06/03/2019] [Indexed: 12/26/2022]
Abstract
Abstract
N-ethylmaleimide-sensitive factor (NSF) disassembles fusion-incompetent cis soluble-NSF attachment protein receptor (SNARE) complexes making monomeric SNAREs available for subsequent trans pairing and fusion. In most cells the activity of NSF is constitutive, but in Jurkat cells and sperm it is repressed by tyrosine phosphorylation; the phosphomimetic mutant NSF–Y83E inhibits secretion in the former. The questions addressed here are if and how the NSF mutant influences the configuration of the SNARE complex. Our model is human sperm, where the initiation of exocytosis (acrosome reaction (AR)) de-represses the activity of NSF through protein tyrosine phosphatase 1B (PTP1B)-mediated dephosphorylation. We developed a fluorescence microscopy-based method to show that capacitation increased, and challenging with an AR inducer decreased, the number of cells with tyrosine-phosphorylated PTP1B substrates in the acrosomal domain. Results from bioinformatic and biochemical approaches using purified recombinant proteins revealed that NSF–Y83E bound PTP1B and thereupon inhibited its catalytic activity. Mutant NSF introduced into streptolysin O-permeabilized sperm impaired cis SNARE complex disassembly, blocking the AR; subsequent addition of PTP1B rescued exocytosis. We propose that NSF–Y83E prevents endogenous PTP1B from dephosphorylating sperm NSF, thus maintaining NSF’s activity in a repressed mode and the SNARE complex unable to dissociate. The contribution of this paper to the sperm biology field is the detection of PTP1B substrates, one of them likely being NSF, whose tyrosine phosphorylation status varies during capacitation and the AR. The contribution of this paper to the membrane traffic field is to have generated direct evidence that explains the dominant-negative role of the phosphomimetic mutant NSF–Y83E.
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Affiliation(s)
- María Celeste Ruete
- Instituto de Histología y Embriología de Mendoza Dr Mario H. Burgos–CONICET, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Valeria Eugenia Paola Zarelli
- Instituto de Histología y Embriología de Mendoza Dr Mario H. Burgos–CONICET, Universidad Nacional de Cuyo, Mendoza, Argentina
- Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Diego Masone
- Instituto de Histología y Embriología de Mendoza Dr Mario H. Burgos–CONICET, Universidad Nacional de Cuyo, Mendoza, Argentina
- Facultad de Ingeniería, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Matilde de Paola
- Instituto de Histología y Embriología de Mendoza Dr Mario H. Burgos–CONICET, Universidad Nacional de Cuyo, Mendoza, Argentina
- Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
- Instituto de Medicina y Biología Experimental de Cuyo–Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Diego Martín Bustos
- Instituto de Histología y Embriología de Mendoza Dr Mario H. Burgos–CONICET, Universidad Nacional de Cuyo, Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Claudia Nora Tomes
- Instituto de Histología y Embriología de Mendoza Dr Mario H. Burgos–CONICET, Universidad Nacional de Cuyo, Mendoza, Argentina
- Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
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17
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Xiong Y, Bedi K, Berritt S, Attipoe BK, Brooks TG, Wang K, Margulies KB, Field J. Targeting MRTF/SRF in CAP2-dependent dilated cardiomyopathy delays disease onset. JCI Insight 2019; 4:124629. [PMID: 30762586 DOI: 10.1172/jci.insight.124629] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 02/12/2019] [Indexed: 12/12/2022] Open
Abstract
About one-third of dilated cardiomyopathy (DCM) cases are caused by mutations in sarcomere or cytoskeletal proteins. However, treating the cytoskeleton directly is not possible because drugs that bind to actin are not well tolerated. Mutations in the actin binding protein CAP2 can cause DCM and KO mice, either whole body (CAP2-KO) or cardiomyocyte-specific KOs (CAP2-CKO) develop DCM with cardiac conduction disease. RNA sequencing analysis of CAP2-KO hearts and isolated cardiomyocytes revealed overactivation of fetal genes, including serum response factor-regulated (SRF-regulated) genes such as Myl9 and Acta2 prior to the emergence of cardiac disease. To test if we could treat CAP2-KO mice, we synthesized and tested the SRF inhibitor CCG-1423-8u. CCG-1423-8u reduced expression of the SRF targets Myl9 and Acta2, as well as the biomarker of heart failure, Nppa. The median survival of CAP2-CKO mice was 98 days, while CCG-1423-8u-treated CKO mice survived for 116 days and also maintained normal cardiac function longer. These results suggest that some forms of sudden cardiac death and cardiac conduction disease are under cytoskeletal stress and that inhibiting signaling through SRF may benefit DCM by reducing cytoskeletal stress.
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Affiliation(s)
- Yao Xiong
- Department of Systems Pharmacology and Translational Therapeutics
| | - Kenneth Bedi
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Simon Berritt
- Department of Chemistry, Merck High throughput Experimentation Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Thomas G Brooks
- Institute of Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kevin Wang
- Department of Systems Pharmacology and Translational Therapeutics
| | - Kenneth B Margulies
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Jeffrey Field
- Department of Systems Pharmacology and Translational Therapeutics
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18
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Layers of Cryptic Genetic Variation Underlie a Yeast Complex Trait. Genetics 2019; 211:1469-1482. [PMID: 30787041 PMCID: PMC6456305 DOI: 10.1534/genetics.119.301907] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 02/14/2019] [Indexed: 01/13/2023] Open
Abstract
To better understand cryptic genetic variation, Lee et al. comprehensively map the genetic basis of a trait that is typically suppressed in a yeast cross. By determining how three different genetic perturbations give rise... Cryptic genetic variation may be an important contributor to heritable traits, but its extent and regulation are not fully understood. Here, we investigate the cryptic genetic variation underlying a Saccharomyces cerevisiae colony phenotype that is typically suppressed in a cross of the laboratory strain BY4716 (BY) and a derivative of the clinical isolate 322134S (3S). To do this, we comprehensively dissect the trait’s genetic basis in the BYx3S cross in the presence of three different genetic perturbations that enable its expression. This allows us to detect and compare the specific loci that interact with each perturbation to produce the trait. In total, we identify 21 loci, all but one of which interact with just a subset of the perturbations. Beyond impacting which loci contribute to the trait, the genetic perturbations also alter the extent of additivity, epistasis, and genotype–environment interaction among the detected loci. Additionally, we show that the single locus interacting with all three perturbations corresponds to the coding region of the cell surface gene FLO11. While nearly all of the other remaining loci influence FLO11 transcription in cis or trans, the perturbations tend to interact with loci in different pathways and subpathways. Our work shows how layers of cryptic genetic variation can influence complex traits. Here, these layers mainly represent different regulatory inputs into the transcription of a single key gene.
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19
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The Small Yeast GTPase Rho5 and Its Dimeric GEF Dck1/Lmo1 Respond to Glucose Starvation. Int J Mol Sci 2018; 19:ijms19082186. [PMID: 30049968 PMCID: PMC6121567 DOI: 10.3390/ijms19082186] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 07/21/2018] [Accepted: 07/23/2018] [Indexed: 12/25/2022] Open
Abstract
Rho5 is a small GTPase of Saccharomyces cerevisiae and a homolog of mammalian Rac1. The latter regulates glucose metabolism and actin cytoskeleton dynamics, and its misregulation causes cancer and a variety of other diseases. In yeast, Rho5 has been implicated in different signal transduction pathways, governing cell wall integrity and the responses to high medium osmolarity and oxidative stress. It has also been proposed to affect mitophagy and apoptosis. Here, we demonstrate that Rho5 rapidly relocates from the plasma membrane to mitochondria upon glucose starvation, mediated by its dimeric GDP/GTP exchange factor (GEF) Dck1/Lmo1. A function in response to glucose availability is also suggested by synthetic genetic phenotypes of a rho5 deletion with gpr1, gpa2, and sch9 null mutants. On the other hand, the role of mammalian Rac1 in regulating the action cytoskeleton does not seem to be strongly conserved in S. cerevisiae Rho5. We propose that Rho5 serves as a central hub in integrating various stress conditions, including a crosstalk with the cAMP/PKA (cyclic AMP activating protein kinase A) and Sch9 branches of glucose signaling pathways.
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20
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Yi DG, Hong S, Huh WK. Mitochondrial dysfunction reduces yeast replicative lifespan by elevating RAS-dependent ROS production by the ER-localized NADPH oxidase Yno1. PLoS One 2018; 13:e0198619. [PMID: 29912878 PMCID: PMC6005541 DOI: 10.1371/journal.pone.0198619] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 05/22/2018] [Indexed: 12/11/2022] Open
Abstract
Mitochondrial dysfunction leads to the accumulation of reactive oxygen species (ROS) which is associated with cellular dysfunction, disease etiology, and senescence. Here, we used the eukaryotic model Saccharomyces cerevisiae, commonly studied for cellular aging, to demonstrate how defective mitochondrial function affects yeast replicative lifespan (RLS). We show that RLS of respiratory-deficient cells decreases significantly, indicating that the maintenance of RLS requires active respiration. The shortening of RLS due to mitochondrial dysfunction was not related to the accumulation of extrachromosomal ribosomal DNA circles, a well-known cause of aging in yeast. Instead, intracellular ROS and oxidatively damaged proteins increased in respiratory-deficient mutants. We show that, while the protein kinase A activity is not elevated, ROS generation in respiratory-deficient cells depends on RAS signaling pathway. The ER-localized NADPH oxidase Yno1 also played a role in producing ROS. Our data suggest that a severe defect in mitochondrial respiration accelerates cellular aging by disturbing protein homeostasis in yeast.
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Affiliation(s)
- Dae-Gwan Yi
- Department of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Sujin Hong
- Department of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Won-Ki Huh
- Department of Biological Sciences, Seoul National University, Seoul, Republic of Korea
- Institute of Microbiology, Seoul National University, Seoul, Republic of Korea
- * E-mail:
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21
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Ras hyperactivation versus overexpression: Lessons from Ras dynamics in Candida albicans. Sci Rep 2018; 8:5248. [PMID: 29588468 PMCID: PMC5869725 DOI: 10.1038/s41598-018-23187-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 03/06/2018] [Indexed: 12/25/2022] Open
Abstract
Ras signaling in response to environmental cues is critical for cellular morphogenesis in eukaryotes. This signaling is tightly regulated and its activation involves multiple players. Sometimes Ras signaling may be hyperactivated. In C. albicans, a human pathogenic fungus, we demonstrate that dynamics of hyperactivated Ras1 (Ras1G13V or Ras1 in Hsp90 deficient strains) can be reliably differentiated from that of normal Ras1 at (near) single molecule level using fluorescence correlation spectroscopy (FCS). Ras1 hyperactivation results in significantly slower dynamics due to actin polymerization. Activating actin polymerization by jasplakinolide can produce hyperactivated Ras1 dynamics. In a sterol-deficient hyperfilamentous GPI mutant of C. albicans too, Ras1 hyperactivation results from Hsp90 downregulation and causes actin polymerization. Hyperactivated Ras1 co-localizes with G-actin at the plasma membrane rather than with F-actin. Depolymerizing actin with cytochalasin D results in faster Ras1 dynamics in these and other strains that show Ras1 hyperactivation. Further, ergosterol does not influence Ras1 dynamics.
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22
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The Yeast Saccharomyces cerevisiae as a Model for Understanding RAS Proteins and their Role in Human Tumorigenesis. Cells 2018; 7:cells7020014. [PMID: 29463063 PMCID: PMC5850102 DOI: 10.3390/cells7020014] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 02/05/2018] [Accepted: 02/12/2018] [Indexed: 12/16/2022] Open
Abstract
The exploitation of the yeast Saccharomyces cerevisiae as a biological model for the investigation of complex molecular processes conserved in multicellular organisms, such as humans, has allowed fundamental biological discoveries. When comparing yeast and human proteins, it is clear that both amino acid sequences and protein functions are often very well conserved. One example of the high degree of conservation between human and yeast proteins is highlighted by the members of the RAS family. Indeed, the study of the signaling pathways regulated by RAS in yeast cells led to the discovery of properties that were often found interchangeable with RAS proto-oncogenes in human pathways, and vice versa. In this work, we performed an updated critical literature review on human and yeast RAS pathways, specifically highlighting the similarities and differences between them. Moreover, we emphasized the contribution of studying yeast RAS pathways for the understanding of human RAS and how this model organism can contribute to unveil the roles of RAS oncoproteins in the regulation of mechanisms important in the tumorigenic process, like autophagy.
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Pentland DR, Piper-Brown E, Mühlschlegel FA, Gourlay CW. Ras signalling in pathogenic yeasts. MICROBIAL CELL 2017; 5:63-73. [PMID: 29417055 PMCID: PMC5798406 DOI: 10.15698/mic2018.02.612] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The small GTPase Ras acts as a master regulator of growth, stress response and cell death in eukaryotic cells. The control of Ras activity is fundamental, as highlighted by the oncogenic properties of constitutive forms of Ras proteins. Ras also plays a crucial role in the pathogenicity of fungal pathogens where it has been found to regulate a number of adaptions required for virulence. The importance of Ras in fungal disease raises the possibility that it may provide a useful target for the development of new treatments at a time when resistance to available antifungals is increasing. New findings suggest that important regulatory sequences found within fungal Ras proteins that are not conserved may prove useful in the development of new antifungals. Here we review the roles of Ras protein function and signalling in the major human yeast pathogens Candida albicans and Cryptococcus neoformans and discuss the potential for targeting Ras as a novel approach to anti-fungal therapy.
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Affiliation(s)
- Daniel R Pentland
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom, CT2 7NJ
| | - Elliot Piper-Brown
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom, CT2 7NJ
| | - Fritz A Mühlschlegel
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom, CT2 7NJ.,Laboratoire national de santé, 1, Rue Louis Rech, L-3555 Dudelange, Luxembourg
| | - Campbell W Gourlay
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom, CT2 7NJ
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Mondo SJ, Lastovetsky OA, Gaspar ML, Schwardt NH, Barber CC, Riley R, Sun H, Grigoriev IV, Pawlowska TE. Bacterial endosymbionts influence host sexuality and reveal reproductive genes of early divergent fungi. Nat Commun 2017; 8:1843. [PMID: 29184190 PMCID: PMC5705715 DOI: 10.1038/s41467-017-02052-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 11/03/2017] [Indexed: 11/09/2022] Open
Abstract
Many heritable mutualisms, in which beneficial symbionts are transmitted vertically between host generations, originate as antagonisms with parasite dispersal constrained by the host. Only after the parasite gains control over its transmission is the symbiosis expected to transition from antagonism to mutualism. Here, we explore this prediction in the mutualism between the fungus Rhizopus microsporus (Rm, Mucoromycotina) and a beta-proteobacterium Burkholderia, which controls host asexual reproduction. We show that reproductive addiction of Rm to endobacteria extends to mating, and is mediated by the symbiont gaining transcriptional control of the fungal ras2 gene, which encodes a GTPase central to fungal reproductive development. We also discover candidate G-protein-coupled receptors for the perception of trisporic acids, mating pheromones unique to Mucoromycotina. Our results demonstrate that regulating host asexual proliferation and modifying its sexual reproduction are sufficient for the symbiont's control of its own transmission, needed for antagonism-to-mutualism transition in heritable symbioses. These properties establish the Rm-Burkholderia symbiosis as a powerful system for identifying reproductive genes in Mucoromycotina.
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Affiliation(s)
- Stephen J Mondo
- School of Integrative Plant Science, Plant Pathology and Plant Microbe-Biology, Cornell University, Ithaca, NY, 14853, USA
- US DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Olga A Lastovetsky
- Graduate Field of Microbiology, Cornell University, Ithaca, NY, 14853, USA
| | - Maria L Gaspar
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Nicole H Schwardt
- School of Integrative Plant Science, Plant Pathology and Plant Microbe-Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Colin C Barber
- School of Integrative Plant Science, Plant Pathology and Plant Microbe-Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Robert Riley
- US DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Hui Sun
- US DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Igor V Grigoriev
- US DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Teresa E Pawlowska
- School of Integrative Plant Science, Plant Pathology and Plant Microbe-Biology, Cornell University, Ithaca, NY, 14853, USA.
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25
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Zhu K, He Q, Li L, Zhao Y, Zhao J. Silencing thioredoxin1 exacerbates damage of astrocytes exposed to OGD/R by aggravating apoptosis through the Actin-Ras2-cAMP-PKA pathway. Int J Neurosci 2017; 128:512-519. [PMID: 29073813 DOI: 10.1080/00207454.2017.1398159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE OF THE STUDY Induction of endogenous antioxidants is one of the key molecular mechanisms of cell resistance to hypoxia/ischemia. Thioredoxin1 (Trx1) is a small multifunctional ubiquitous antioxidant with redox-active dithiol and plays an important role in cell apoptosis through mitochondrial apoptosis pathways. The specific role of Trx1 in ischemia-reperfusion induced astrocyte apoptosis, however, remains unclear. MATERIALS AND METHODS In this study, we investigated the effect of Trx1 on apoptosis of astrocyte using an in vitro oxygen-glucose deprivation/reoxygenation (OGD/R) model which mimics ischemic/reperfusion conditions in vivo. The astrocytes prepared from newborn Sprague-Dawley rats were exposed to OGD for 4 h followed by reoxygenation for 24 h. Next, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used to assess cell viability while cell damage was assessed by lactate dehydrogenase (LDH). RESULTS We found that OGD/R increased cell death as well as the expression of Trx1 and that the interference of Trx1 further aggravated astrocyte damage under OGD/R condition. Furthermore, we detected an increase in the intracellular expressions of Ras2, cAMP, and PKA under OGD/R condition, which paralleled cell injury. CONCLUSIONS Notably, the deletion of Trx1 exacerbated astrocyte apoptosis via the Ras2-cAMP-PKA signaling pathway. We concluded that Trx1 protects astrocytes against apoptotic injury induced by OGD/R, and this protective effect may be partly related to the Ras2-cAMP-PKA signaling pathway.
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Affiliation(s)
- Kunting Zhu
- a Department of Pathology , The First People's Hospital of Yibin , Yibin , Sichuan , People's Republic of China
| | - Qi He
- b Department of Pathophysiology , Chongqing Medical University , Chongqing , People's Republic of China.,c Institute of Neuroscience , Chongqing Medical University , Chongqing , PR China
| | - Lingyu Li
- c Institute of Neuroscience , Chongqing Medical University , Chongqing , PR China.,d Department of Pathology , Chongqing Medical University , Chongqing , People's Republic of China
| | - Yong Zhao
- c Institute of Neuroscience , Chongqing Medical University , Chongqing , PR China.,d Department of Pathology , Chongqing Medical University , Chongqing , People's Republic of China
| | - Jing Zhao
- b Department of Pathophysiology , Chongqing Medical University , Chongqing , People's Republic of China.,c Institute of Neuroscience , Chongqing Medical University , Chongqing , PR China
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Fructose-1,6-bisphosphate couples glycolytic flux to activation of Ras. Nat Commun 2017; 8:922. [PMID: 29030545 PMCID: PMC5640605 DOI: 10.1038/s41467-017-01019-z] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/14/2017] [Indexed: 12/12/2022] Open
Abstract
Yeast and cancer cells share the unusual characteristic of favoring fermentation of sugar over respiration. We now reveal an evolutionary conserved mechanism linking fermentation to activation of Ras, a major regulator of cell proliferation in yeast and mammalian cells, and prime proto-oncogene product. A yeast mutant (tps1∆) with overactive influx of glucose into glycolysis and hyperaccumulation of Fru1,6bisP, shows hyperactivation of Ras, which causes its glucose growth defect by triggering apoptosis. Fru1,6bisP is a potent activator of Ras in permeabilized yeast cells, likely acting through Cdc25. As in yeast, glucose triggers activation of Ras and its downstream targets MEK and ERK in mammalian cells. Biolayer interferometry measurements show that physiological concentrations of Fru1,6bisP stimulate dissociation of the pure Sos1/H-Ras complex. Thermal shift assay confirms direct binding to Sos1, the mammalian ortholog of Cdc25. Our results suggest that the Warburg effect creates a vicious cycle through Fru1,6bisP activation of Ras, by which enhanced fermentation stimulates oncogenic potency. Yeast and cancer cells both favor sugar fermentation in aerobic conditions. Here the authors describe a conserved mechanism from yeast to mammals where the glycolysis intermediate fructose-1,6-bisphosphate binds Cdc25/Sos1 and couples increased glycolytic flux to increased Ras proto-oncoprotein activity.
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Induction of apoptosis and ganoderic acid biosynthesis by cAMP signaling in Ganoderma lucidum. Sci Rep 2017; 7:318. [PMID: 28336949 PMCID: PMC5428012 DOI: 10.1038/s41598-017-00281-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/20/2017] [Indexed: 12/21/2022] Open
Abstract
Apoptosis is an essential physiological process that controls many important biological functions. However, apoptosis signaling in relation to secondary metabolite biosynthesis in plants and fungi remains a mystery. The fungus Ganoderma lucidum is a popular herbal medicine worldwide, but the biosynthetic regulation of its active ingredients (ganoderic acids, GAs) is poorly understood. We investigated the role of 3′,5′-cyclic adenosine monophosphate (cAMP) signaling in fungal apoptosis and GA biosynthesis in G. lucidum. Two phosphodiesterase inhibitors (caffeine and 3-isobutyl-1-methylxanthine, IBMX) and an adenylate cyclase activator (sodium fluoride, NaF) were used to increase intracellular cAMP levels. Fungal apoptosis was identified by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay and a condensed nuclear morphology. Our results showed that GA production and fungal apoptosis were induced when the mycelium was treated with NaF, caffeine, or cAMP/IBMX. Downregulation of squalene synthase and lanosterol synthase gene expression by cAMP was detected in the presence of these chemicals, which indicates that these two genes are not critical for GA induction. Transcriptome analysis indicated that mitochondria might play an important role in cAMP-induced apoptosis and GA biosynthesis. To the best of our knowledge, this is the first report to reveal that cAMP signaling induces apoptosis and secondary metabolite production in fungi.
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Sudakov NP, Klimenkov IV, Byvaltsev VA, Nikiforov SB, Konstantinov YM. Extracellular Actin in Health and Disease. BIOCHEMISTRY (MOSCOW) 2017; 82:1-12. [PMID: 28320282 DOI: 10.1134/s0006297917010011] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This review considers the functions of extracellular actin - cell surface bound, associated with extracellular matrix, or freely circulating. The role of this protein in different pathological processes is analyzed: its toxic effects and involvement in autoimmune diseases as an autoantigen. The extracellular actin clearance system and its role in protection against the negative effects of actin are characterized. Levels of free-circulating actin, anti-actin immunoglobulins, and components of the actin clearance system as prognostic biomarkers for different diseases are reviewed. Experimental approaches to protection against excessive amounts of free-circulating F-actin are discussed.
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Affiliation(s)
- N P Sudakov
- Irkutsk Surgery and Traumatology Research Center, Irkutsk, 664003, Russia.
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Qi T, Wang J, Sun Q, Day B, Guo J, Ma Q. TaARPC3, Contributes to Wheat Resistance against the Stripe Rust Fungus. FRONTIERS IN PLANT SCIENCE 2017; 8:1245. [PMID: 28769954 PMCID: PMC5513970 DOI: 10.3389/fpls.2017.01245] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 06/30/2017] [Indexed: 05/19/2023]
Abstract
The actin cytoskeleton participates in numerous cellular processes, including less-characterized processes, such as nuclear organization, chromatin remodeling, transcription, and signal transduction. As a key regulator of actin cytoskeletal dynamics, the actin related protein 2/3 complex (Arp2/3 complex) controls multiple developmental processes in a variety of tissues and cell types. To date, the role of the Arp2/3 complex in plant disease resistance signaling is largely unknown. Herein, we identified and characterized wheat ARPC3, TaARPC3, which encodes the C3 subunit of the Arp2/3 complex. Expression of TaARPC3 in the arc18 mutant of Saccharomyces cerevisiae Δarc18 resulted in complementation of stress-induced phenotypes in S. cerevisiae, as well as restore wild-type cell shape malformations. TaARPC3 was found predominantly to be localized in the nucleus and cytoplasm when expressed transiently in wheat protoplast. TaARPC3 was significantly induced in response to avirulent race of Puccinia striiformis f. sp. tritici (Pst). Knock-down of TaARPC3 by virus-induced gene silencing resulted in a reduction of resistance against Pst through a specific reduction in actin cytoskeletal organization. Interestingly, this reduction was found to coincide with a block in reactive oxygen species (ROS) accumulation, the hypersensitive response (HR), an increase in TaCAT1 mRNA accumulation, and the growth of Pst. Taken together, these findings suggest that TaARPC3 is a key subunit of the Arp2/3 complex which is required for wheat resistance against Pst, a process that is associated with the regulation of the actin cytoskeleton.
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Affiliation(s)
- Tuo Qi
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Juan Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Qixiong Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F UniversityYangling, China
| | - Brad Day
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East LansingMI, United States
- Plant Resilience Institute, Michigan State University, East LansingMI, United States
| | - Jun Guo
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F UniversityYangling, China
- *Correspondence: Qing Ma, Jun Guo,
| | - Qing Ma
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F UniversityYangling, China
- *Correspondence: Qing Ma, Jun Guo,
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Yi DG, Kim MJ, Choi JE, Lee J, Jung J, Huh WK, Chung WH. Yap1 and Skn7 genetically interact with Rad51 in response to oxidative stress and DNA double-strand break in Saccharomyces cerevisiae. Free Radic Biol Med 2016; 101:424-433. [PMID: 27838435 DOI: 10.1016/j.freeradbiomed.2016.11.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 10/17/2016] [Accepted: 11/04/2016] [Indexed: 12/01/2022]
Abstract
Reactive oxygen species (ROS)-mediated DNA adducts as well as DNA strand breaks are highly mutagenic leading to genomic instability and tumorigenesis. DNA damage repair pathways and oxidative stress response signaling have been proposed to be highly associated, but the underlying interaction remains unknown. In this study, we employed mutant strains lacking Rad51, the homolog of E. coli RecA recombinase, and Yap1 or Skn7, two major transcription factors responsive to ROS, to examine genetic interactions between double-strand break (DSB) repair proteins and cellular redox regulators in budding yeast Saccharomyces cerevisiae. Abnormal expression of YAP1 or SKN7 aggravated the mutation rate of rad51 mutants and their sensitivity to DSB- or ROS-generating reagents. Rad51 deficiency exacerbated genome instability in the presence of increased levels of ROS, and the accumulation of DSB lesions resulted in elevated intracellular ROS levels. Our findings suggest that evident crosstalk between DSB repair pathways and ROS signaling proteins contributes to cell survival and maintenance of genome integrity in response to genotoxic stress.
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Affiliation(s)
- Dae Gwan Yi
- Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 08826, Republic of Korea
| | - Myung Ju Kim
- College of Pharmacy, Duksung Women's University, Seoul 01369, Republic of Korea; Innovative Drug Center, Duksung Women's University, Seoul 01369, Republic of Korea
| | - Ji Eun Choi
- College of Pharmacy, Duksung Women's University, Seoul 01369, Republic of Korea; Innovative Drug Center, Duksung Women's University, Seoul 01369, Republic of Korea
| | - Jihyun Lee
- College of Pharmacy, Duksung Women's University, Seoul 01369, Republic of Korea; Innovative Drug Center, Duksung Women's University, Seoul 01369, Republic of Korea
| | - Joohee Jung
- College of Pharmacy, Duksung Women's University, Seoul 01369, Republic of Korea; Innovative Drug Center, Duksung Women's University, Seoul 01369, Republic of Korea
| | - Won-Ki Huh
- Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 08826, Republic of Korea
| | - Woo-Hyun Chung
- College of Pharmacy, Duksung Women's University, Seoul 01369, Republic of Korea; Innovative Drug Center, Duksung Women's University, Seoul 01369, Republic of Korea.
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Effects of heterologous expression of human cyclic nucleotide phosphodiesterase 3A (hPDE3A) on redox regulation in yeast. Biochem J 2016; 473:4205-4225. [PMID: 27647936 DOI: 10.1042/bcj20160572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 09/07/2016] [Accepted: 09/19/2016] [Indexed: 01/11/2023]
Abstract
Oxidative stress plays a pivotal role in pathogenesis of cardiovascular diseases and diabetes; however, the roles of protein kinase A (PKA) and human phosphodiesterase 3A (hPDE3A) remain unknown. Here, we show that yeast expressing wild-type (WT) hPDE3A or K13R hPDE3A (putative ubiquitinylation site mutant) exhibited resistance or sensitivity to exogenous hydrogen peroxide (H2O2), respectively. H2O2-stimulated ROS production was markedly increased in yeast expressing K13R hPDE3A (Oxidative stress Sensitive 1, OxiS1), compared with yeast expressing WT hPDE3A (Oxidative stress Resistant 1, OxiR1). In OxiR1, YAP1 and YAP1-dependent antioxidant genes were up-regulated, accompanied by a reduction in thioredoxin peroxidase. In OxiS1, expression of YAP1 and YAP1-dependent genes was impaired, and the thioredoxin system malfunctioned. H2O2 increased cyclic adenosine monophosphate (cAMP)-hydrolyzing activity of WT hPDE3A, but not K13R hPDE3A, through PKA-dependent phosphorylation of hPDE3A, which was correlated with its ubiquitinylation. The changes in antioxidant gene expression did not directly correlate with differences in cAMP-PKA signaling. Despite differences in their capacities to hydrolyze cAMP, total cAMP levels among OxiR1, OxiS1, and mock were similar; PKA activity, however, was lower in OxiS1 than in OxiR1 or mock. During exposure to H2O2, however, Sch9p activity, a target of Rapamycin complex 1-regulated Rps6 kinase and negative-regulator of PKA, was rapidly reduced in OxiR1, and Tpk1p, a PKA catalytic subunit, was diffusely spread throughout the cytosol, with PKA activation. In OxiS1, Sch9p activity was unchanged during exposure to H2O2, consistent with reduced activation of PKA. These results suggest that, during oxidative stress, TOR-Sch9 signaling might regulate PKA activity, and that post-translational modifications of hPDE3A are critical in its regulation of cellular recovery from oxidative stress.
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Gao N, Wadhwani P, Mühlhäuser P, Liu Q, Riemann M, Ulrich AS, Nick P. An antifungal protein from Ginkgo biloba binds actin and can trigger cell death. PROTOPLASMA 2016; 253:1159-74. [PMID: 26315821 DOI: 10.1007/s00709-015-0876-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/17/2015] [Indexed: 06/04/2023]
Abstract
Ginkbilobin is a short antifungal protein that had been purified and cloned from the seeds of the living fossil Ginkgo biloba. Homologues of this protein can be detected in all seed plants and the heterosporic fern Selaginella and are conserved with respect to domain structures, peptide motifs, and specific cysteine signatures. To get insight into the cellular functions of these conserved motifs, we expressed green fluorescent protein fusions of full-length and truncated ginkbilobin in tobacco BY-2 cells. We show that the signal peptide confers efficient secretion of ginkbilobin. When this signal peptide is either cleaved or masked, ginkbilobin binds and visualizes the actin cytoskeleton. This actin-binding activity of ginkbilobin is mediated by a specific subdomain just downstream of the signal peptide, and this subdomain can also coassemble with actin in vitro. Upon stable overexpression of this domain, we observe a specific delay in premitotic nuclear positioning indicative of a reduced dynamicity of actin. To elucidate the cellular response to the binding of this subdomain to actin, we use chemical engineering based on synthetic peptides comprising different parts of the actin-binding subdomain conjugated with the cell-penetrating peptide BP100 and with rhodamine B as a fluorescent reporter. Binding of this synthetic construct to actin efficiently induces programmed cell death. We discuss these findings in terms of a working model, where ginkbilobin can activate actin-dependent cell death.
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Affiliation(s)
- Ningning Gao
- Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany
| | - Parvesh Wadhwani
- Institute for Biological Interfaces (IBG-2), KIT, P.O. Box 3640, 76021, Karlsruhe, Germany
| | - Philipp Mühlhäuser
- Institute for Biological Interfaces (IBG-2), KIT, P.O. Box 3640, 76021, Karlsruhe, Germany
| | - Qiong Liu
- Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany
| | - Michael Riemann
- Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany
| | - Anne S Ulrich
- Institute for Biological Interfaces (IBG-2), KIT, P.O. Box 3640, 76021, Karlsruhe, Germany
- Institute of Organic Chemistry and CFN, KIT, Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Peter Nick
- Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany.
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Taylor MB, Phan J, Lee JT, McCadden M, Ehrenreich IM. Diverse genetic architectures lead to the same cryptic phenotype in a yeast cross. Nat Commun 2016; 7:11669. [PMID: 27248513 PMCID: PMC4895441 DOI: 10.1038/ncomms11669] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 04/18/2016] [Indexed: 01/09/2023] Open
Abstract
Cryptic genetic variants that do not typically influence traits can interact epistatically with each other and mutations to cause unexpected phenotypes. To improve understanding of the genetic architectures and molecular mechanisms that underlie these interactions, we comprehensively dissected the genetic bases of 17 independent instances of the same cryptic colony phenotype in a yeast cross. In eight cases, the phenotype resulted from a genetic interaction between a de novo mutation and one or more cryptic variants. The number and identities of detected cryptic variants depended on the mutated gene. In the nine remaining cases, the phenotype arose without a de novo mutation due to two different classes of higher-order genetic interactions that only involve cryptic variants. Our results may be relevant to other species and disease, as most of the mutations and cryptic variants identified in our study reside in components of a partially conserved and oncogenic signalling pathway. Cryptic genetic variants may not individually show discernible phenotypic effects, but collectively, these polymorphisms can lead to unexpected, genetically complex traits that might be relevant to evolution and disease. Here, the authors use large yeast populations to comprehensively dissect the genetic bases of 17 independent occurrences of a phenotype that arises due to combinations of epistatically interacting cryptic variants.
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Affiliation(s)
- Matthew B Taylor
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
| | - Joann Phan
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
| | - Jonathan T Lee
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
| | - Madelyn McCadden
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
| | - Ian M Ehrenreich
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
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Abstract
Apoptosis or programmed cell death (PCD) was initially described in metazoans as a genetically controlled process leading to intracellular breakdown and engulfment by a neighboring cell . This process was distinguished from other forms of cell death like necrosis by maintenance of plasma membrane integrity prior to engulfment and the well-defined genetic system controlling this process. Apoptosis was originally described as a mechanism to reshape tissues during development. Given this context, the assumption was made that this process would not be found in simpler eukaryotes such as budding yeast. Although basic components of the apoptotic pathway were identified in yeast, initial observations suggested that it was devoid of prosurvival and prodeath regulatory proteins identified in mammalian cells. However, as apoptosis became extensively linked to the elimination of damaged cells, key PCD regulatory proteins were identified in yeast that play similar roles in mammals. This review highlights recent discoveries that have permitted information regarding PCD regulation in yeast to now inform experiments in animals.
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Lee JT, Taylor MB, Shen A, Ehrenreich IM. Multi-locus Genotypes Underlying Temperature Sensitivity in a Mutationally Induced Trait. PLoS Genet 2016; 12:e1005929. [PMID: 26990313 PMCID: PMC4798298 DOI: 10.1371/journal.pgen.1005929] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 02/21/2016] [Indexed: 01/24/2023] Open
Abstract
Determining how genetic variation alters the expression of heritable phenotypes across conditions is important for agriculture, evolution, and medicine. Central to this problem is the concept of genotype-by-environment interaction (or 'GxE'), which occurs when segregating genetic variation causes individuals to show different phenotypic responses to the environment. While many studies have sought to identify individual loci that contribute to GxE, obtaining a deeper understanding of this phenomenon may require defining how sets of loci collectively alter the relationship between genotype, environment, and phenotype. Here, we identify combinations of alleles at seven loci that control how a mutationally induced colony phenotype is expressed across a range of temperatures (21, 30, and 37 °C) in a panel of yeast recombinants. We show that five predominant multi-locus genotypes involving the detected loci result in trait expression with varying degrees of temperature sensitivity. By comparing these genotypes and their patterns of trait expression across temperatures, we demonstrate that the involved alleles contribute to temperature sensitivity in different ways. While alleles of the transcription factor MSS11 specify the potential temperatures at which the trait can occur, alleles at the other loci modify temperature sensitivity within the range established by MSS11 in a genetic background- and/or temperature-dependent manner. Our results not only represent one of the first characterizations of GxE at the resolution of multi-locus genotypes, but also provide an example of the different roles that genetic variants can play in altering trait expression across conditions.
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Affiliation(s)
- Jonathan T. Lee
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
| | - Matthew B. Taylor
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
| | - Amy Shen
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
| | - Ian M. Ehrenreich
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
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Lucchesi O, Ruete MC, Bustos MA, Quevedo MF, Tomes CN. The signaling module cAMP/Epac/Rap1/PLCε/IP3 mobilizes acrosomal calcium during sperm exocytosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:544-61. [PMID: 26704387 DOI: 10.1016/j.bbamcr.2015.12.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 11/23/2015] [Accepted: 12/14/2015] [Indexed: 12/29/2022]
Abstract
Exocytosis of the sperm's single secretory granule, or acrosome, is a regulated exocytosis triggered by components of the egg's investments. In addition to external calcium, sperm exocytosis (termed the acrosome reaction) requires cAMP synthesized endogenously and calcium mobilized from the acrosome through IP3-sensitive channels. The relevant cAMP target is Epac. In the first part of this paper, we present a novel tool (the TAT-cAMP sponge) to investigate cAMP-related signaling pathways in response to progesterone as acrosome reaction trigger. The TAT-cAMP sponge consists of the cAMP-binding sites of protein kinase A regulatory subunit RIβ fused to the protein transduction domain TAT of the human immunodeficiency virus-1. The sponge permeated into sperm, sequestered endogenous cAMP, and blocked exocytosis. Progesterone increased the population of sperm with Rap1-GTP, Rab3-GTP, and Rab27-GTP in the acrosomal region; pretreatment with the TAT-cAMP sponge prevented the activation of all three GTPases. In the second part of this manuscript, we show that phospholipase Cε (PLCε) is required for the acrosome reaction downstream of Rap1 and upstream of intra-acrosomal calcium mobilization. Last, we present direct evidence that cAMP, Epac, Rap1, and PLCε are necessary for calcium mobilization from sperm's secretory granule. In summary, we describe here a pathway that connects cAMP to calcium mobilization from the acrosome during sperm exocytosis. Never before had direct evidence for each step of the cascade been put together in the same study.
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Affiliation(s)
- Ornella Lucchesi
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza 5500, Argentina
| | - María C Ruete
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza 5500, Argentina
| | - Matías A Bustos
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza 5500, Argentina
| | - María F Quevedo
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza 5500, Argentina
| | - Claudia N Tomes
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza 5500, Argentina.
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Rozycki M, Bialik JF, Speight P, Dan Q, Knudsen TET, Szeto SG, Yuen DA, Szászi K, Pedersen SF, Kapus A. Myocardin-related Transcription Factor Regulates Nox4 Protein Expression: LINKING CYTOSKELETAL ORGANIZATION TO REDOX STATE. J Biol Chem 2015; 291:227-43. [PMID: 26555261 DOI: 10.1074/jbc.m115.674606] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Indexed: 01/06/2023] Open
Abstract
TGFβ-induced expression of the NADPH oxidase Nox4 is essential for fibroblast-myofibroblast transition. Rho has been implicated in Nox4 regulation, but the underlying mechanisms are largely unknown. Myocardin-related transcription factor (MRTF), a Rho/actin polymerization-controlled coactivator of serum response factor, drives myofibroblast transition from various precursors. We have shown that TGFβ is necessary but insufficient for epithelial-myofibroblast transition in intact epithelia; the other prerequisite is the uncoupling of intercellular contacts, which induces Rho-dependent nuclear translocation of MRTF. Because the Nox4 promoter harbors a serum response factor/MRTF cis-element (CC(A/T)6GG box), we asked if MRTF (and thus cytoskeleton organization) could regulate Nox4 expression. We show that Nox4 protein is robustly induced in kidney tubular cells exclusively by combined application of contact uncoupling and TGFβ. Nox4 knockdown abrogates epithelial-myofibroblast transition-associated reactive oxygen species production. Laser capture microdissection reveals increased Nox4 expression in the tubular epithelium also during obstructive nephropathy. MRTF down-regulation/inhibition suppresses TGFβ/contact disruption-provoked Nox4 protein and mRNA expression, Nox4 promoter activation, and reactive oxygen species production. Mutation of the CC(A/T)6GG box eliminates the synergistic activation of the Nox4 promoter. Jasplakinolide-induced actin polymerization synergizes with TGFβ to facilitate MRTF-dependent Nox4 mRNA expression/promoter activation. Moreover, MRTF inhibition prevents Nox4 expression during TGFβ-induced fibroblast-myofibroblast transition as well. Although necessary, MRTF is insufficient; Nox4 expression also requires TGFβ-activated Smad3 and TAZ/YAP, two contact- and cytoskeleton-regulated Smad3-interacting coactivators. Down-regulation/inhibition of TAZ/YAP mitigates injury-induced epithelial Nox4 expression in vitro and in vivo. These findings uncover new MRTF- and TAZ/YAP-dependent mechanisms, which link cytoskeleton remodeling and redox state and impact epithelial plasticity and myofibroblast transition.
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Affiliation(s)
- Matthew Rozycki
- From the Keenan Research Centre for Biomedical Science of the St. Michael's Hospital
| | - Janne Folke Bialik
- From the Keenan Research Centre for Biomedical Science of the St. Michael's Hospital, the Department of Biology, Section for Cell Biology and Physiology, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Pam Speight
- From the Keenan Research Centre for Biomedical Science of the St. Michael's Hospital
| | - Qinghong Dan
- From the Keenan Research Centre for Biomedical Science of the St. Michael's Hospital
| | - Teresa E T Knudsen
- the Department of Biology, Section for Cell Biology and Physiology, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Stephen G Szeto
- From the Keenan Research Centre for Biomedical Science of the St. Michael's Hospital
| | - Darren A Yuen
- From the Keenan Research Centre for Biomedical Science of the St. Michael's Hospital
| | - Katalin Szászi
- From the Keenan Research Centre for Biomedical Science of the St. Michael's Hospital, Departments of Surgery and
| | - Stine F Pedersen
- the Department of Biology, Section for Cell Biology and Physiology, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - András Kapus
- From the Keenan Research Centre for Biomedical Science of the St. Michael's Hospital, Departments of Surgery and Biochemistry, University of Toronto, Toronto, Ontario M5B 1T8, Canada and
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Zhou Y, Zhang S, Deng S, Dai C, Tang S, Yang X, Li D, Zhao K, Xiao X. ML-7 amplifies the quinocetone-induced cell death through akt and MAPK-mediated apoptosis on HepG2 cell line. Toxicol Mech Methods 2015; 26:11-21. [DOI: 10.3109/15376516.2015.1090513] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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The Stationary-Phase Cells of Saccharomyces cerevisiae Display Dynamic Actin Filaments Required for Processes Extending Chronological Life Span. Mol Cell Biol 2015; 35:3892-908. [PMID: 26351139 DOI: 10.1128/mcb.00811-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 08/31/2015] [Indexed: 11/20/2022] Open
Abstract
Stationary-growth-phase Saccharomyces cerevisiae yeast cultures consist of nondividing cells that undergo chronological aging. For their successful survival, the turnover of proteins and organelles, ensured by autophagy and the activation of mitochondria, is performed. Some of these processes are engaged in by the actin cytoskeleton. In S. cerevisiae stationary-phase cells, F actin has been shown to form static aggregates named actin bodies, subsequently cited to be markers of quiescence. Our in vivo analyses revealed that stationary-phase cultures contain cells with dynamic actin filaments, besides the cells with static actin bodies. The cells with dynamic actin displayed active endocytosis and autophagy and well-developed mitochondrial networks. Even more, stationary-phase cell cultures grown under calorie restriction predominantly contained cells with actin cables, confirming that the presence of actin cables is linked to successful adaptation to stationary phase. Cells with actin bodies were inactive in endocytosis and autophagy and displayed aberrations in mitochondrial networks. Notably, cells of the respiratory activity-deficient cox4Δ strain displayed the same mitochondrial aberrations and actin bodies only. Additionally, our results indicate that mitochondrial dysfunction precedes the formation of actin bodies and the appearance of actin bodies corresponds to decreased cell fitness. We conclude that the F-actin status reflects the extent of damage that arises from exponential growth.
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Pereira H, Oliveira CSF, Castro L, Preto A, Chaves SR, Côrte-Real M. Yeast as a tool to explore cathepsin D function. MICROBIAL CELL 2015; 2:225-234. [PMID: 28357298 PMCID: PMC5349170 DOI: 10.15698/mic2015.07.212] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cathepsin D has garnered increased attention in recent years, mainly since it has been associated with several human pathologies. In particular, cathepsin D is often overexpressed and hypersecreted in cancer cells, implying it may constitute a therapeutic target. However, cathepsin D can have both anti- and pro-survival functions depending on its proteolytic activity, cellular context and stress stimulus. Therefore, a more detailed understanding of cathepsin D regulation and how to modulate its apoptotic functions is clearly needed. In this review, we provide an overview of the role of cathepsin D in physiological and pathological scenarios. We then focus on the opposing functions of cathepsin D in apoptosis, particularly relevant in cancer research. Emphasis is given to the role of the yeast protease Pep4p, the vacuolar counterpart of cathepsin D, in life and death. Finally, we discuss how insights from yeast cathepsin D and its role in regulated cell death can unveil novel functions of mammalian cathepsin D in apoptosis and cancer.
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Affiliation(s)
- H Pereira
- CBMA- Centre of Molecular and Environmental Biology. Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - C S F Oliveira
- CBMA- Centre of Molecular and Environmental Biology. Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal. ; ICBAS - Institute of Biomedical Sciences Abel Salazar, University of Porto, 4050-313, Porto, Portugal
| | - L Castro
- CBMA- Centre of Molecular and Environmental Biology. Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - A Preto
- CBMA- Centre of Molecular and Environmental Biology. Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - S R Chaves
- CBMA- Centre of Molecular and Environmental Biology. Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - M Côrte-Real
- CBMA- Centre of Molecular and Environmental Biology. Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
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Uhlemann R, Gertz K, Boehmerle W, Schwarz T, Nolte C, Freyer D, Kettenmann H, Endres M, Kronenberg G. Actin dynamics shape microglia effector functions. Brain Struct Funct 2015; 221:2717-34. [PMID: 25989853 DOI: 10.1007/s00429-015-1067-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 05/15/2015] [Indexed: 11/28/2022]
Abstract
Impaired actin filament dynamics have been associated with cellular senescence. Microglia, the resident immune cells of the brain, are emerging as a central pathophysiological player in neurodegeneration. Microglia activation, which ranges on a continuum between classical and alternative, may be of critical importance to brain disease. Using genetic and pharmacological manipulations, we studied the effects of alterations in actin dynamics on microglia effector functions. Disruption of actin dynamics did not affect transcription of genes involved in the LPS-triggered classical inflammatory response. By contrast, in consequence of impaired nuclear translocation of phospho-STAT6, genes involved in IL-4 induced alternative activation were strongly downregulated. Functionally, impaired actin dynamics resulted in reduced NO secretion and reduced release of TNFalpha and IL-6 from LPS-stimulated microglia and of IGF-1 from IL-4 stimulated microglia. However, pathological stabilization of the actin cytoskeleton increased LPS-induced release of IL-1beta and IL-18, which belong to an unconventional secretory pathway. Reduced NO release was associated with decreased cytoplasmic iNOS protein expression and decreased intracellular arginine uptake. Furthermore, disruption of actin dynamics resulted in reduced microglia migration, proliferation and phagocytosis. Finally, baseline and ATP-induced [Ca(2+)]int levels were significantly increased in microglia lacking gelsolin, a key actin-severing protein. Together, the dynamic state of the actin cytoskeleton profoundly and distinctly affects microglia behaviours. Disruption of actin dynamics attenuates M2 polarization by inhibiting transcription of alternative activation genes. In classical activation, the role of actin remodelling is complex, does not relate to gene transcription and shows a major divergence between cytokines following conventional and unconventional secretion.
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Affiliation(s)
- Ria Uhlemann
- Klinik und Hochschulambulanz für Neurologie, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Karen Gertz
- Klinik und Hochschulambulanz für Neurologie, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.,Klinik und Poliklinik für Neurologie and Center for Stroke Research Berlin (CSB), Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Wolfgang Boehmerle
- Klinik und Hochschulambulanz für Neurologie, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Tobias Schwarz
- Klinik und Hochschulambulanz für Neurologie, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Christiane Nolte
- Cellular Neuroscience, Max-Delbruck-Center for Molecular Medicine, 13092, Berlin-Buch, Germany
| | - Dorette Freyer
- Klinik und Hochschulambulanz für Neurologie, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Helmut Kettenmann
- Cellular Neuroscience, Max-Delbruck-Center for Molecular Medicine, 13092, Berlin-Buch, Germany
| | - Matthias Endres
- Klinik und Hochschulambulanz für Neurologie, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany. .,Klinik und Poliklinik für Neurologie and Center for Stroke Research Berlin (CSB), Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany. .,Excellence Cluster NeuroCure, 10117, Berlin, Germany. .,German Center for Cardiovascular Research (DZHK), 13347, Berlin, Germany.
| | - Golo Kronenberg
- Klinik und Hochschulambulanz für Neurologie, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany. .,Klinik und Poliklinik für Neurologie and Center for Stroke Research Berlin (CSB), Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany. .,Klinik und Poliklinik für Psychiatrie und Psychotherapie, Charité Universitätsmedizin Berlin, 10117, Berlin, Germany.
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Pyatrikas DV, Fedoseeva IV, Varakina NN, Rusaleva TM, Stepanov AV, Fedyaeva AV, Borovskii GB, Rikhvanov EG. Relation between cell death progression, reactive oxygen species production and mitochondrial membrane potential in fermenting Saccharomyces cerevisiae cells under heat-shock conditions. FEMS Microbiol Lett 2015; 362:fnv082. [DOI: 10.1093/femsle/fnv082] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2015] [Indexed: 12/21/2022] Open
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Liu Y, Liu N, Wu D, Bi Q, Meng S. The longevity of tor1Δ, sch9Δ, and ras2Δ mutants depends on actin dynamics in Saccharomyces cerevisiae. Cell Biosci 2015; 5:18. [PMID: 25901273 PMCID: PMC4404670 DOI: 10.1186/s13578-015-0008-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 03/31/2015] [Indexed: 02/07/2023] Open
Abstract
Recent studies have revealed the role of actin dynamics in the regulation of yeast aging. Although the target of rapamycin (TOR) complex, serine/threonine kinase Sch9, and Ras2 have been shown to play important roles in aging for a long time, the relationship between these regulators and actin has not yet been reported. In this study we investigated the roles of actin polarization in tor1Δ, sch9Δ, and ras2Δ mutant cells. We found that the actin structures in tor1Δ, sch9Δ, and ras2Δ mutant cells were more dynamic than those in the wild type. Destruction of the actin structures with jasplakinolide decreased the life span of tor1Δ, sch9Δ, and ras2Δ mutants. Furthermore, deletion of SLA1 in tor1Δ, sch9Δ, and ras2Δ mutants inhibited the actin dynamics and life span. In addition, we found that the actin cytoskeleton of the long-lived mutant sch9Δ, depended on the transcription factors RIM15 and MSN2/4, but not GIS1, while the actin skeleton of the tor1Δ and ras2Δ mutants depended on RIM15 as expected. Our data suggest that the longevity of tor1Δ, sch9Δ, and ras2Δ mutants is dependent on actin dynamics.
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Affiliation(s)
- Ying Liu
- Department of Biochemistry and Molecular Biology, Key Laboratory of Cell Biology, Ministry of Public Health, China Medical University, Shenyang, 110001, P. R. China
| | - Nanqi Liu
- Department of Biochemistry and Molecular Biology, Key Laboratory of Cell Biology, Ministry of Public Health, China Medical University, Shenyang, 110001, P. R. China
| | - Didi Wu
- Department of Biochemistry and Molecular Biology, Key Laboratory of Cell Biology, Ministry of Public Health, China Medical University, Shenyang, 110001, P. R. China
| | - Qiang Bi
- Department of Biochemistry and Molecular Biology, Key Laboratory of Cell Biology, Ministry of Public Health, China Medical University, Shenyang, 110001, P. R. China
| | - Shengnan Meng
- Department of Pharmaceutics, Pharmacy school of China Medical University, Shenyang, 110001 P. R. China
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Dettmann A, Heilig Y, Valerius O, Ludwig S, Seiler S. Fungal communication requires the MAK-2 pathway elements STE-20 and RAS-2, the NRC-1 adapter STE-50 and the MAP kinase scaffold HAM-5. PLoS Genet 2014; 10:e1004762. [PMID: 25411845 PMCID: PMC4239118 DOI: 10.1371/journal.pgen.1004762] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 09/18/2014] [Indexed: 11/30/2022] Open
Abstract
Intercellular communication is critical for the survival of unicellular organisms as well as for the development and function of multicellular tissues. Cell-to-cell signaling is also required to develop the interconnected mycelial network characteristic of filamentous fungi and is a prerequisite for symbiotic and pathogenic host colonization achieved by molds. Somatic cell–cell communication and subsequent cell fusion is governed by the MAK-2 mitogen activated protein kinase (MAPK) cascade in the filamentous ascomycete model Neurospora crassa, yet the composition and mode of regulation of the MAK-2 pathway are currently unclear. In order to identify additional components involved in MAK-2 signaling we performed affinity purification experiments coupled to mass spectrometry with strains expressing functional GFP-fusion proteins of the MAPK cascade. This approach identified STE-50 as a regulatory subunit of the Ste11p homolog NRC-1 and HAM-5 as cell-communication-specific scaffold protein of the MAPK cascade. Moreover, we defined a network of proteins consisting of two Ste20-related kinases, the small GTPase RAS-2 and the adenylate cyclase capping protein CAP-1 that function upstream of the MAK-2 pathway and whose signals converge on the NRC-1/STE-50 MAP3K complex and the HAM-5 scaffold. Finally, our data suggest an involvement of the striatin interacting phosphatase and kinase (STRIPAK) complex, the casein kinase 2 heterodimer, the phospholipid flippase modulators YPK-1 and NRC-2 and motor protein-dependent vesicle trafficking in the regulation of MAK-2 pathway activity and function. Taken together, these data will have significant implications for our mechanistic understanding of MAPK signaling and for homotypic cell–cell communication in fungi and higher eukaryotes. Appropriate cellular responses to external stimuli depend on the highly orchestrated activity of interconnected signaling cascades. One crucial level of control arises from the formation of discrete complexes through scaffold proteins that bind multiple components of a given pathway. Central for our understanding of these signaling platforms is the archetypical MAP kinase scaffold Ste5p, a protein that is restricted to budding yeast and close relatives. We identified HAM-5, a protein highly conserved in filamentous ascomycete fungi, as cell–cell communication-specific scaffold protein of the Neurospora crassa MAK-2 cascade (homologous to the budding yeast pheromone pathway). We also describe a network of upstream acting proteins, consisting of two Ste20-related kinases, the small G-protein RAS-2 and the adenylate cyclase capping protein CAP-1, whose signals converge on HAM-5. Our work has implications for the mechanistic understanding of MAP kinase scaffold proteins and their function during intercellular communication in eukaryotic microbes as well as higher eukaryotes.
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Affiliation(s)
- Anne Dettmann
- Institute for Biology II – Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Yvonne Heilig
- Institute for Biology II – Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Oliver Valerius
- Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
| | - Sarah Ludwig
- Institute for Biology II – Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Stephan Seiler
- Institute for Biology II – Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs University Freiburg, Freiburg, Germany
- * E-mail:
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45
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Desouza M, Gunning PW, Stehn JR. The actin cytoskeleton as a sensor and mediator of apoptosis. BIOARCHITECTURE 2014; 2:75-87. [PMID: 22880146 PMCID: PMC3414384 DOI: 10.4161/bioa.20975] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Apoptosis is an important biological process required for the removal of unwanted or damaged cells. Mounting evidence implicates the actin cytoskeleton as both a sensor and mediator of apoptosis. Studies also suggest that actin binding proteins (ABPs) significantly contribute to apoptosis and that actin dynamics play a key role in regulating apoptosis signaling. Changes in the organization of the actin cytoskeleton has been attributed to the process of malignant transformation and it is hypothesized that remodeling of the actin cytoskeleton may enable tumor cells to evade normal apoptotic signaling. This review aims to illuminate the role of the actin cytoskeleton in apoptosis by systematically analyzing how actin and ABPs regulate different apoptosis pathways and to also highlight the potential for developing novel compounds that target tumor-specific actin filaments.
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Affiliation(s)
- Melissa Desouza
- Oncology Research Unit; School of Medical Sciences; The University of New South Wales; Sydney, Australia
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46
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Ras GTPase activating protein CoIra1 is involved in infection-related morphogenesis by regulating cAMP and MAPK signaling pathways through CoRas2 in Colletotrichum orbiculare. PLoS One 2014; 9:e109045. [PMID: 25275394 PMCID: PMC4183519 DOI: 10.1371/journal.pone.0109045] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 08/29/2014] [Indexed: 11/19/2022] Open
Abstract
Colletotrichum orbiculare is the causative agent of anthracnose disease on cucurbitaceous plants. Several signaling pathways, including cAMP–PKA and mitogen-activating protein kinase (MAPK) pathways are involved in the infection-related morphogenesis and pathogenicity of C. orbiculare. However, upstream regulators of these pathways for this species remain unidentified. In this study, CoIRA1, encoding RAS GTPase activating protein, was identified by screening the Agrobacterium tumefaciens-mediated transformation (AtMT) mutant, which was defective in the pathogenesis of C. orbiculare. The coira1 disrupted mutant showed an abnormal infection-related morphogenesis and attenuated pathogenesis. In Saccharomyces cerevisiae, Ira1/2 inactivates Ras1/2, which activates adenylate cyclase, leading to the synthesis of cAMP. Increase in the intracellular cAMP levels in coira1 mutants and dominant active forms of CoRAS2 introduced transformants indicated that CoIra1 regulates intracellular cAMP levels through CoRas2. Moreover, the phenotypic analysis of transformants that express dominant active form CoRAS2 in the comekk1 mutant or a dominant active form CoMEKK1 in the coras2 mutant indicated that CoRas2 regulates the MAPK CoMekk1–Cmk1 signaling pathway. The CoRas2 localization pattern in vegetative hyphae of the coira1 mutant was similar to that of the wild-type, expressing a dominant active form of RFP–CoRAS2. Moreover, we demonstrated that bimolecular fluorescence complementation (BiFC) signals between CoIra1 and CoRas2 were detected in the plasma membrane of vegetative hyphae. Therefore, it is likely that CoIra1 negatively regulates CoRas2 in vegetative hyphae. Furthermore, cytological analysis of the localization of CoIraI and CoRas2 revealed the dynamic cellular localization of the proteins that leads to proper assembly of F-actin at appressorial pore required for successful penetration peg formation through the pore. Thus, our results indicated that CoIra1 is involved in infection-related morphogenesis and pathogenicity by proper regulation of cAMP and MAPK signaling pathways through CoRas2.
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47
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Frost B, Götz J, Feany MB. Connecting the dots between tau dysfunction and neurodegeneration. Trends Cell Biol 2014; 25:46-53. [PMID: 25172552 DOI: 10.1016/j.tcb.2014.07.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 07/22/2014] [Accepted: 07/24/2014] [Indexed: 11/18/2022]
Abstract
Tauopathies are devastating and ultimately fatal neurodegenerative diseases, which are histopathologically defined by insoluble filamentous deposits of abnormally phosphorylated tau protein within neurons and glia. Identifying the causes of abnormal tau phosphorylation and subsequent aggregation has been the focus of much research, and is currently a major target for the development of therapeutic interventions for tauopathies, including Alzheimer's disease (AD). Much has recently been learned about the sequence of events that lead from tau dysfunction to neuronal death. This review focuses on the cascade of events that are catalyzed by pathological tau, and highlights current and potential therapeutic strategies to target this pathway.
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Affiliation(s)
- Bess Frost
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jürgen Götz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Mel B Feany
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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48
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Aghamohammadzadeh S, Smaczynska-de Rooij II, Ayscough KR. An Abp1-dependent route of endocytosis functions when the classical endocytic pathway in yeast is inhibited. PLoS One 2014; 9:e103311. [PMID: 25072293 PMCID: PMC4114835 DOI: 10.1371/journal.pone.0103311] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 06/30/2014] [Indexed: 12/04/2022] Open
Abstract
Clathrin-mediated endocytosis (CME) is a well characterized pathway in both yeast and mammalian cells. An increasing number of alternative endocytic pathways have now been described in mammalian cells that can be both clathrin, actin, and Arf6- dependent or independent. In yeast, a single clathrin-mediated pathway has been characterized in detail. However, disruption of this pathway in many mutant strains indicates that other uptake pathways might exist, at least for bulk lipid and fluid internalization. Using a combination of genetics and live cell imaging, here we show evidence for a novel endocytic pathway in S. cerevisiae that does not involve several of the proteins previously shown to be associated with the ‘classic’ pathway of endocytosis. This alternative pathway functions in the presence of low levels of the actin-disrupting drug latrunculin-A which inhibits movement of the proteins Sla1, Sla2, and Sac6, and is independent of dynamin function. We reveal that in the absence of the ‘classic’ pathway, the actin binding protein Abp1 is now essential for bulk endocytosis. This novel pathway appears to be distinct from another described alternative endocytic route in S. cerevisiae as it involves at least some proteins known to be associated with cortical actin patches rather than being mediated at formin-dependent endocytic sites. These data indicate that cells have the capacity to use overlapping sets of components to facilitate endocytosis under a range of conditions.
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Affiliation(s)
| | | | - Kathryn R. Ayscough
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
- * E-mail:
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49
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Ono S. The role of cyclase-associated protein in regulating actin filament dynamics - more than a monomer-sequestration factor. J Cell Sci 2014; 126:3249-58. [PMID: 23908377 DOI: 10.1242/jcs.128231] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Dynamic reorganization of the actin cytoskeleton is fundamental to a number of cell biological events. A variety of actin-regulatory proteins modulate polymerization and depolymerization of actin and contribute to actin cytoskeletal reorganization. Cyclase-associated protein (CAP) is a conserved actin-monomer-binding protein that has been studied for over 20 years. Early studies have shown that CAP sequesters actin monomers; recent studies, however, have revealed more active roles of CAP in actin filament dynamics. CAP enhances the recharging of actin monomers with ATP antagonistically to ADF/cofilin, and also promotes the severing of actin filaments in cooperation with ADF/cofilin. Self-oligomerization and binding to other proteins regulate activities and localization of CAP. CAP has crucial roles in cell signaling, development, vesicle trafficking, cell migration and muscle sarcomere assembly. This Commentary discusses the recent advances in our understanding of the functions of CAP and its implications as an important regulator of actin cytoskeletal dynamics, which are involved in various cellular activities.
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Affiliation(s)
- Shoichiro Ono
- Department of Pathology and Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
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50
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Alanazi I, Ebrahimie E, Hoffmann P, Adelson DL. Combined gene expression and proteomic analysis of EGF induced apoptosis in A431 cells suggests multiple pathways trigger apoptosis. Apoptosis 2014; 18:1291-1305. [PMID: 23892916 DOI: 10.1007/s10495-013-0887-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A431 cells, derived from epidermoid carcinoma, overexpress the epidermal growth factor receptor (EGFR) and when treated with a high dose of EGF will undergo apoptosis. We exploited microarray and proteomics techniques and network prediction to study the regulatory mechanisms of EGF-induced apoptosis in A431 cells. We observed significant changes in gene expression in 162 genes, approximately evenly split between pro-apoptotic and anti-apoptotic genes and identified 30 proteins from the proteomic data that had either pro or anti-apoptotic annotation. Our correlation analysis of gene expression and proteome modeled a number of distinct sub-networks that are associated with the onset of apoptosis, allowing us to identify specific pathways and components. These include components of the interferon signalling pathway, and down stream components, including cytokines and suppressors of cytokine signalling. A central component of almost all gene expression sub-networks identified was TP53, which is mutated in A431 cells, and was down regulated. This down regulation of TP53 appeared to be correlated with proteomic sub-networks of cytoskeletal or cell adhesion components that might induce apoptosis by triggering cytochrome C release. Of the only three genes also differentially expressed as proteins, only serpinb1 had a known association with apoptosis. We confirmed that up regulation and cleavage of serpinb1 into L-DNAaseII was correlated with the induction of apoptosis. It is unlikely that a single pathway, but more likely a combination of pathways is needed to trigger EGF induced apoptosis in A431cells.
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Affiliation(s)
- Ibrahim Alanazi
- School of Molecular & Biomedical Science, The University of Adelaide, Adelaide, SA, Australia
| | - Esmaeil Ebrahimie
- School of Molecular & Biomedical Science, The University of Adelaide, Adelaide, SA, Australia
| | - Peter Hoffmann
- School of Molecular & Biomedical Science, The University of Adelaide, Adelaide, SA, Australia
| | - David L Adelson
- School of Molecular & Biomedical Science, The University of Adelaide, Adelaide, SA, Australia.
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