scholarly journals Cell Wall Integrity MAPK Pathway Is Essential for Lipid Homeostasis

2008 ◽  
Vol 283 (49) ◽  
pp. 34204-34217 ◽  
Author(s):  
Lilia R. Nunez ◽  
Stephen A. Jesch ◽  
Maria L. Gaspar ◽  
Claudia Almaguer ◽  
Manuel Villa-Garcia ◽  
...  
Keyword(s):  
Cell Wall ◽  
Mapk Pathway ◽  
Cell Wall Integrity ◽  
Lipid Homeostasis

scholarly journals Yeast Nap1-Binding Protein Nbp2p Is Required for Mitotic Growth at High Temperatures and for Cell Wall Integrity

Genetics ◽  
2003 ◽  
Vol 165 (2) ◽  
pp. 517-529
Author(s):  
Kentaro Ohkuni ◽  
Asuko Okuda ◽  
Akihiko Kikuchi
Keyword(s):  
Cell Death ◽  
Cell Wall ◽  
High Temperature ◽  
High Temperatures ◽  
Hybrid System ◽  
Mapk Pathway ◽  
Binding Protein ◽  
Cell Wall Integrity ◽  
Calcofluor White ◽  
Two Hybrid

AbstractNbp2p is a Nap1-binding protein in Saccharomyces cerevisiae identified by its interaction with Nap1 by a two-hybrid system. NBP2 encodes a novel protein consisting of 236 amino acids with a Src homology 3 (SH3) domain. We showed that NBP2 functions to promote mitotic cell growth at high temperatures and cell wall integrity. Loss of Nbp2 results in cell death at high temperatures and in sensitivity to calcofluor white. Cell death at high temperature is thought not to be due to a weakened cell wall. Additionally, we have isolated several type-2C serine threonine protein phosphatases (PTCs) as multicopy suppressors and MAP kinase-kinase (MAPKK), related to the yeast PKC MAPK pathway, as deletion suppressors of the nbp2Δ mutant. Screening for deletion suppressors is a new genetic approach to identify and characterize additional proteins in the Nbp2-dependent pathway. Genetic analyses suggested that Ptc1, which interacts with Nbp2 by the two-hybrid system, acts downstream of Nbp2 and that cells lacking the function of Nbp2 prefer to lose Mkk1, but the PKC MAPK pathway itself is indispensable when Nbp2 is deleted at high temperature.

Activation of the yeast cell wall integrity MAPK pathway by zymolyase depends on protease and glucanase activities and requires the mucin-like protein Hkr1 but not Msb2

FEBS Letters ◽  
2013 ◽  
Vol 587 (22) ◽  
pp. 3675-3680 ◽  
Author(s):  
José M. Rodríguez-Peña ◽  
Sonia Díez-Muñiz ◽  
Clara Bermejo ◽  
César Nombela ◽  
Javier Arroyo
Keyword(s):  
Cell Wall ◽  
Yeast Cell ◽  
Mapk Pathway ◽  
Cell Wall Integrity ◽  
Yeast Cell Wall

scholarly journals Septins coordinate cell wall integrity and lipid metabolism in a sphingolipid-dependent process

2021 ◽  
pp. jcs.258336
Author(s):  
Alexander Mela ◽  
Michelle Momany
Keyword(s):  
Cell Wall ◽  
Mapk Pathway ◽  
Single Agent ◽  
Cell Wall Integrity ◽  
Sphingolipid Metabolism ◽  
Null Mutant ◽  
The Core ◽  
Increased Sensitivity ◽  
Multiple Cell ◽  
Polysaccharide Composition

Septins colocalize with membrane sterol-rich regions and facilitate recruitment of cell wall synthases during wall remodeling. We show that null mutants missing an Aspergillus nidulans core septin present in hexamers and octamers (ΔaspAcdc11, ΔaspBcdc3, or ΔaspCcdc12) are sensitive to multiple cell wall-disturbing agents that activate the cell wall integrity MAPK pathway. The null mutant missing the octamer-exclusive core septin (ΔaspDcdc10) showed similar sensitivity, but only to a single cell wall-disturbing agent and the null mutant missing the noncore septin (ΔaspE) showed very mild sensitivity to a different single agent. Core septin mutants showed changes in wall polysaccharide composition and chitin synthase localization. Mutants missing any of the five septins resisted ergosterol-disrupting agents. Hexamer mutants showed increased sensitivity to sphingolipid-disrupting agents. Core septins mislocalized after treatment with sphingolipid-disrupting agents, but not after ergosterol-disrupting agents. Our data suggest that the core septins are involved in cell wall integrity signaling; that all five septins are involved in monitoring ergosterol metabolism; that the hexamer septins are required for sphingolipid metabolism; and that septins require sphingolipids to coordinate the cell wall integrity response.

scholarly journals Septins coordinate cell wall integrity and lipid metabolism in a sphingolipid-dependent process

2020 ◽  
Author(s):  
Alexander Mela ◽  
Michelle Momany
Keyword(s):  
Cell Wall ◽  
Mapk Pathway ◽  
Single Agent ◽  
Cell Wall Integrity ◽  
Sphingolipid Metabolism ◽  
Minor Role ◽  
Cell Wall Polysaccharide ◽  
Null Mutant ◽  
A Minor ◽  
Null Mutants

AbstractDuring normal development and response to environmental stress, fungi must coordinate synthesis of the cell wall and plasma membrane. Septins, small cytoskeletal GTPases, colocalize with membrane sterol-rich regions and facilitate recruitment of cell wall synthases during dynamic wall remodeling. In this study we show that null mutants missing an Aspergillus nidulans core septin present in hexamers and octamers (ΔaspAcdc11, ΔaspBcdc3, or ΔaspCcdc12) are sensitive to multiple cell wall-disturbing agents known to activate the cell wall integrity MAPK pathway and that this sensitivity can be remediated by osmotic support. The null mutant missing the octamer-exclusive core septin (ΔaspDcdc10) showed similar osmotic-remedial sensitivity, but only to a single cell wall-disturbing agent and the null mutant missing the noncore septin (ΔaspE) showed very mild osmotic-remedial sensitivity to a different single agent. Representative core septin null mutants showed changes in cell wall polysaccharide composition, organization, and chitin synthase localization. Double mutant analysis with ΔmpkA suggested core septins interact with the cell wall integrity pathway. Null mutants missing any of the five septins were resistant to ergosterol-disrupting agents. The ΔaspAcdc11, ΔaspBcdc3, and ΔaspCcdc12 mutants showed increased sensitivity to sphingolipid-disrupting agents that was remediated by addition of exogenous phytosphingosine. Representative core septins were mislocalized after treatment with sphingolipid-disrupting agents, but not after treatment with ergosterol-disrupting agents. When challenged with both sphingolipid-disturbing and cell wall-disturbing agents in combination, remediation of the lipid defect restored proper growth to ΔaspAcdc11, ΔaspBcdc3, and ΔaspCcdc12, but remediation of the cell wall defect did not. Our data suggest that the core hexamer and octamer septins are involved in cell wall integrity signaling with the noncore septin playing a minor role; that all five septins are involved in monitoring ergosterol metabolism; that the hexamer septins are required for sphingolipid metabolism; and that septins require sphingolipids to coordinate the cell wall integrity response.

scholarly journals Chromatin remodeling by the SWI/SNF complex is essential for transcription mediated by the yeast cell wall integrity MAPK pathway

2012 ◽  
Vol 23 (14) ◽  
pp. 2805-2817 ◽  
Author(s):  
A. Belén Sanz ◽  
Raúl García ◽  
Jose Manuel Rodríguez-Peña ◽  
Sonia Díez-Muñiz ◽  
César Nombela ◽  
...  
Keyword(s):  
Cell Wall ◽  
Chromatin Remodeling ◽  
Mapk Pathway ◽  
Critical Role ◽  
Transcriptional Response ◽  
Wall Stress ◽  
Cell Wall Integrity ◽  
Mitogen Activated Protein Kinase ◽  
Cell Wall Stress ◽  
Mitogen Activated Protein

In Saccharomyces cerevisiae, the transcriptional program triggered by cell wall stress is coordinated by Slt2/Mpk1, the mitogen-activated protein kinase (MAPK) of the cell wall integrity (CWI) pathway, and is mostly mediated by the transcription factor Rlm1. Here we show that the SWI/SNF chromatin-remodeling complex plays a critical role in orchestrating the transcriptional response regulated by Rlm1. swi/snf mutants show drastically reduced expression of cell wall stress–responsive genes and hypersensitivity to cell wall–interfering compounds. On stress, binding of RNA Pol II to the promoters of these genes depends on Rlm1, Slt2, and SWI/SNF. Rlm1 physically interacts with SWI/SNF to direct its association to target promoters. Finally, we observe nucleosome displacement at the CWI-responsive gene MLP1/KDX1, which relies on the SWI/SNF complex. Taken together, our results identify the SWI/SNF complex as a key element of the CWI MAPK pathway that mediates the chromatin remodeling necessary for adequate transcriptional response to cell wall stress.

scholarly journals Clotrimazole-Induced Oxidative Stress Triggers Novel Yeast Pkc1-Independent Cell Wall Integrity MAPK Pathway Circuitry

2021 ◽  
Vol 7 (8) ◽  
pp. 647
Author(s):  
Ángela Sellers-Moya ◽  
Marcos Nuévalos ◽  
María Molina ◽  
Humberto Martín
Keyword(s):  
Oxidative Stress ◽  
Cell Wall ◽  
Stress Responses ◽  
Fungal Infections ◽  
Mapk Pathway ◽  
Mapk Signaling ◽  
Cell Wall Integrity ◽  
Strong Impact ◽  
Yeast Saccharomyces Cerevisiae ◽  
Activation Motif

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.

scholarly journals The Fungal Cell-Wall Integrity MAPK Cascade Is Crucial for Hyphal Network Formation and Maintenance of Restrictive Growth of Epichloë festucae in Symbiosis With Lolium perenne

2015 ◽  
Vol 28 (1) ◽  
pp. 69-85 ◽  
Author(s):  
Yvonne Becker ◽  
Carla J. Eaton ◽  
Emma Brasell ◽  
Kimberley J. May ◽  
Matthias Becker ◽  
...  
Keyword(s):  
Cell Wall ◽  
Lolium Perenne ◽  
Network Formation ◽  
Mapk Pathway ◽  
Cell Wall Integrity ◽  
Mitogen Activated Protein Kinase ◽  
Vascular Bundles ◽  
Intercellular Spaces ◽  
Symbiotic Interaction ◽  
Epichloë Festucae

Epichloë festucae is a mutualistic symbiont that systemically colonizes the intercellular spaces of Lolium perenne leaves to form a highly structured and interconnected hyphal network. In an Agrobacterium tumefaciens T-DNA forward genetic screen, we identified a mutant TM1066 that had a severe host interaction phenotype, causing stunting and premature senescence of the host. Molecular analysis revealed that the mutation responsible for this phenotype was in the cell-wall integrity (CWI) mitogen-activated protein kinase kinase (MAPKK), mkkA. Mutants generated by targeted deletion of the mkkA or the downstream mpkA kinase recapitulated the phenotypes observed for TM1066. Both mutants were defective in hyphal cell–cell fusion, formed intrahyphal hyphae, had enhanced conidiation, and showed microcyclic conidiation. Transmission electron microscopy and confocal microscopy analysis of leaf tissue showed that mutant hyphae were more abundant than the wild type in the intercellular spaces and colonized the vascular bundles. Hyphal branches failed to fuse but, instead, grew past one another to form bundles of convoluted hyphae. Mutant hyphae showed increased fluorescence with AF488-WGA, indicative of increased accessibility of chitin, a hypothesis supported by changes in the cell-wall ultrastructure. These results show that the CWI MAPK pathway is a key signaling pathway for controlling the mutualistic symbiotic interaction between E. festucae and L. perenne.

scholarly journals Heat-Shock Proteins MoSsb1, MoSsz1, and MoZuo1 Attenuate MoMkk1-Mediated Cell-Wall Integrity Signaling and Are Important for Growth and Pathogenicity of Magnaporthe oryzae

2018 ◽  
Vol 31 (11) ◽  
pp. 1211-1221 ◽  
Author(s):  
Jie Yang ◽  
Muxing Liu ◽  
Xinyu Liu ◽  
Ziyi Yin ◽  
Yi Sun ◽  
...  
Keyword(s):  
Cell Wall ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Magnaporthe Oryzae ◽  
Mapk Pathway ◽  
Cell Wall Integrity ◽  
Mitogen Activated Protein Kinase ◽  
Blast Fungus ◽  
High Amino Acid ◽  
Shock Proteins

The mitogen-activated protein kinase (MAPK) MoMkk1 governs the cell-wall integrity (CWI) pathway in rice blast fungus Magnaporthe oryzae. To understand the underlying mechanism, we have identified MoSsb1 as one of the MoMkk1-interacting proteins. MoSsb1 is a stress-seventy subfamily B (Ssb) protein homolog, sharing high amino acid sequence homology with the 70-kDa heat shock proteins (Hsp70s). Hsp70 are a family of conserved and ubiquitously expressed chaperones that regulate protein biogenesis by promoting protein folding, preventing protein aggregation, and controlling protein degradation. We found that MoSsb1 regulates the synthesis of nascent polypeptide chains and this regulation is achieved by being in complex with other members of Hsp70s MoSsz1 and 40-kDa Hsp40 MoZuo1. MoSsb1 is important for the growth, conidiation, and full virulence of the blast fungus and this role is also shared by MoSsz1 and MoZuo1. Importantly, MoSsb1, MoSsz1, and MoZuo1 are all involved in the regulation of the CWI MAPK pathway by modulating MoMkk1 biosynthesis. Our studies reveal novel insights into how MoSsb1, MoSsz1, and MoZuo1 affect CWI signaling that is involved in regulating growth, differentiation, and virulence of M. oryzae and highlight the conserved functional mechanisms of heat-shock proteins in pathogenic fungi.

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