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

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.

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

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ran Liu ◽  
Zhenqi Su ◽  
Huiyan Zhou ◽  
Qian Huang ◽  
Shuangxi Fan ◽  
...  

Abstract High temperatures have significant impacts on heat-tolerant bolting in lettuce. In this study, it was found that high temperatures could facilitate the accumulation of GA in lettuce to induce bolting, with higher expression levels of two heat shock protein genes LsHsp70-3701 and LsHsp70-2711. By applying VIGS technology, these two Hsp70 genes were incompletely silenced and plant morphological changes under heat treatment of silenced plants were observed. The results showed that lower expression levels of these two genes could enhance bolting stem length of lettuce under high temperatures, which means these two proteins may play a significant role in heat-induced bolting tolerance. By using the yeast two-hybrid technique, it was found that a calmodulin protein could interact with LsHsp70 proteins in a high-temperature stress cDNA library, which was constructed for lettuce. Also, the Hsp70-calmodulin combination can be obtained at high temperatures. According to these results, it can be speculated that the interaction between Hsp70 and calmodulin could be induced under high temperatures and higher GA contents can be obtained at the same time. This study analyses the regulation of heat tolerance in lettuce and lays a foundation for additional studies of heat resistance in lettuce.


2019 ◽  
Vol 30 (4) ◽  
pp. 441-452 ◽  
Author(s):  
Allison E. Hall ◽  
Mark D. Rose

During mating, Saccharomyces cerevisiae cells must degrade the intervening cell wall to allow fusion of the partners. Because improper timing or location of cell wall degradation would cause lysis, the initiation of cell fusion must be highly regulated. Here, we find that yeast cell fusion is negatively regulated by components of the cell wall integrity (CWI) pathway. Loss of the cell wall sensor, MID2, specifically causes “mating-induced death” after pheromone exposure. Mating-induced death is suppressed by mutations in cell fusion genes ( FUS1, FUS2, RVS161, CDC42), implying that mid2Δ cells die from premature fusion without a partner. Consistent with premature fusion, mid2Δ shmoos had thinner cell walls and lysed at the shmoo tip. Normally, Cdc42p colocalizes with Fus2p to form a focus only when mating cells are in contact (prezygotes) and colocalization is required for cell fusion. However, Cdc42p was aberrantly colocalized with Fus2p to form a focus in mid2Δ shmoos. A hyperactive allele of the CWI kinase Pkc1p ( PKC1*) caused decreased cell fusion and Cdc42p localization in prezygotes. In shmoos, PKC1* increased Cdc42p localization; however, it was not colocalized with Fus2p or associated with cell death. We conclude that Mid2p and Pkc1p negatively regulate cell fusion via Cdc42p and Fus2p.


2013 ◽  
Vol 58 (1) ◽  
pp. 167-175 ◽  
Author(s):  
Awanish Kumar ◽  
Sanjiveeni Dhamgaye ◽  
Indresh Kumar Maurya ◽  
Ashutosh Singh ◽  
Monika Sharma ◽  
...  

ABSTRACTCurcumin (CUR) shows antifungal activity against a range of pathogenic fungi, includingCandida albicans. The reported mechanisms of action of CUR include reactive oxygen species (ROS) generation, defects in the ergosterol biosynthesis pathway, decrease in hyphal development, and modulation of multidrug efflux pumps. Reportedly, each of these pathways is independently linked to the cell wall machinery inC. albicans, but surprisingly, CUR has not been previously implicated in cell wall damage. In the present study, we performed transcriptional profiling to identify the yet-unidentified targets of CUR inC. albicans. We found that, among 348 CUR-affected genes, 51 were upregulated and 297 were downregulated. Interestingly, most of the cell wall integrity pathway genes were downregulated. The possibility of the cell wall playing a critical role in the mechanism of CUR required further validation; therefore, we performed specific experiments to establish if there was any link between the two. The fractional inhibitory concentration index values of 0.24 to 0.37 show that CUR interacts synergistically with cell wall-perturbing (CWP) agents (caspofungin, calcofluor white, Congo red, and SDS). Furthermore, we could observe cell wall damage and membrane permeabilization by CUR alone, as well as synergistically with CWP agents. We also found hypersusceptibility in calcineurin and mitogen-activated protein (MAP) kinase pathway mutants against CUR, which confirmed that CUR also targets cell wall biosynthesis inC. albicans. Together, these data provide strong evidence that CUR disrupts cell wall integrity inC. albicans. This new information on the mechanistic action of CUR could be employed in improving treatment strategies and in combinatorial drug therapy.


2003 ◽  
Vol 278 (43) ◽  
pp. 42487-42494 ◽  
Author(s):  
Teruo Sugawara ◽  
Hiroshi Shimizu ◽  
Nobuhiko Hoshi ◽  
Ayako Nakajima ◽  
Seiichiro Fujimoto

2022 ◽  
Author(s):  
Yu Zhang ◽  
Mengyan Li ◽  
Hanying Wang ◽  
Juqing Deng ◽  
Jianxing Liu ◽  
...  

Abstract The mechanism of fungal cell wall synthesis and assembly is still unclear. Saccharomyces cerevisiae (S. cerevisiae) and pathogenic fungi are conserved in cell wall construction and response to stress signals, and often respond to cell wall stress through activated cell wall integrity (CWI) pathways. Whether the YLR358C open reading frame regulates CWI remains unclear. This study found that the growth of S. cerevisiae with YLR358C knockout was significantly inhibited on the medium containing different concentrations of cell wall interfering agents Calcofluor White (CFW), Congo Red (CR) and sodium dodecyl sulfate (SDS). CFW staining showed that the cell wall chitin was down-regulated, and transmission electron microscopy also observed a decrease in cell wall thickness. Transcriptome sequencing and analysis showed that YLR358C gene may be involved in the regulation of CWI signaling pathway. It was found by qRT-PCR that WSC3, SWI4 and HSP12 were differentially expressed after YLR358C was knocked out. The above results suggest that YLR358C may regulate the integrity of the yeast cell walls and has some potential for application in fermentation.


Author(s):  
Guanggan Hu ◽  
Linda Horianopoulos ◽  
Eddy Sánchez-León ◽  
Mélissa Caza ◽  
Wonhee Jung ◽  
...  

Abstract Monothiol glutaredoxins are important regulators of iron homeostasis that play conserved roles in the sensing and trafficking of iron-sulfur clusters. We previously characterized the role of the monothiol glutaredoxin Grx4 in iron homeostasis, the interaction with the iron regulator Cir1, and virulence in Cryptococcus neoformans. This important fungal pathogen causes cryptococcal meningoencephalitis in immunocompromised individuals worldwide. Here, we demonstrate that Grx4 is required for proliferation at elevated temperatures (both 37°C and 39°C) and under stress conditions. In particular, the grx4Δ mutant was hypersensitive to SDS, calcofluor white (CFW), and caffeine, suggesting that Grx4 is required for membrane and cell wall integrity (CWI). In this context, we found that Grx4 regulated the phosphorylation of the Mpk1 mitogen-activated protein kinase (MAPK) of the CWI pathway in cells grown at elevated temperature or upon treatment with CFW, caffeine, or SDS. The grx4Δ mutant also displayed increased sensitivity to FK506 and cyclosporin A, two inhibitors of the calcineurin pathway, indicating that Grx4 may influence growth at higher temperatures in parallel with calcineurin signaling. Upon thermal stress or calcium treatment, loss of Grx4 also caused partial mis-localization of Crz1, the transcription factor that is a calcineurin substrate. The phenotypes of the grx4Δ, crz1Δ, and cna1Δ (calcineurin) mutants suggest shared contributions to the regulation of temperature, cell wall, and other stresses. In summary, we show that Grx4 is also a key regulator of the responses to a variety of stress conditions in addition to its roles in iron homeostasis in C. neoformans.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Jingjin Hu ◽  
Yachen Dong ◽  
Wei Wang ◽  
Wei Zhang ◽  
Hanghang Lou ◽  
...  

Abstract Background Programmed cell death (PCD) induced by acetic acid, the main by-product released during cellulosic hydrolysis, cast a cloud over lignocellulosic biofuel fermented by Saccharomyces cerevisiae and became a burning problem. Atg22p, an ignored integral membrane protein located in vacuole belongs to autophagy-related genes family; prior study recently reported that it is required for autophagic degradation and efflux of amino acids from vacuole to cytoplasm. It may alleviate the intracellular starvation of nutrition caused by Ac and increase cell tolerance. Therefore, we investigate the role of atg22 in cell death process induced by Ac in which attempt is made to discover new perspectives for better understanding of the mechanisms behind tolerance and more robust industrial strain construction. Results In this study, we compared cell growth, physiological changes in the absence and presence of Atg22p under Ac exposure conditions. It is observed that disruption and overexpression of Atg22p delays and enhances acetic acid-induced PCD, respectively. The deletion of Atg22p in S. cerevisiae maintains cell wall integrity, and protects cytomembrane integrity, fluidity and permeability upon Ac stress by changing cytomembrane phospholipids, sterols and fatty acids. More interestingly, atg22 deletion increases intracellular amino acids to aid yeast cells for tackling amino acid starvation and intracellular acidification. Further, atg22 deletion upregulates series of stress response genes expression such as heat shock protein family, cell wall integrity and autophagy. Conclusions The findings show that Atg22p possessed the new function related to cell resistance to Ac. This may help us have a deeper understanding of PCD induced by Ac and provide a new strategy to improve Ac resistance in designing industrial yeast strains for bioethanol production during lignocellulosic biofuel fermentation.


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