scholarly journals The fission yeast pmk1+ gene encodes a novel mitogen-activated protein kinase homolog which regulates cell integrity and functions coordinately with the protein kinase C pathway.

1996 ◽  
Vol 16 (12) ◽  
pp. 6752-6764 ◽  
Author(s):  
T Toda ◽  
S Dhut ◽  
G Superti-Furga ◽  
Y Gotoh ◽  
E Nishida ◽  
...  
Keyword(s):  
Cell Wall ◽  
Protein Kinase C ◽  
Amino Acid ◽  
Protein Kinase ◽  
Fission Yeast ◽  
Mitogen Activated Protein Kinase ◽  
Cell Integrity ◽  
Kinase C ◽  
Mitogen Activated Protein ◽  
Mapk Gene

We have isolated a gene, pmk1+, a third mitogen-activated protein kinase (MAPK) gene homolog from the fission yeast Schizosaccharomyces pombe. The predicted amino acid sequence shows the most homology (63 to 65% identity) to those of budding yeast Saccharomyces Mpk1 and Candida Mkc1. The Pmk1 protein contains phosphorylated tyrosines, and the level of tyrosine phosphorylation was increased in the dsp1 mutant which lacks an attenuating phosphatase for Pmk1. The level of tyrosine phosphorylation appears constant during hypotonic or heat shock treatment. The cells with pmk1 deleted (delta pmk1) are viable but show various defective phenotypes, including cell wall weakness, abnormal cell shape, a cytokinesis defect, and altered sensitivities to cations, such as hypersensitivity to potassium and resistance to sodium. Consistent with a high degree of conservation of amino acid sequence, multicopy plasmids containing the MPK1 gene rescued the defective phenotypes of the delta pmk1 mutant. The frog MAPK gene also suppressed the pmk1 disruptant. The results of genetic analysis indicated that Pmk1 lies on a novel MAPK pathway which does not overlap functionally with the other two MAPK pathways, the Spk1-dependent mating signal pathway and Sty1/Spc1/Phh1-dependent stress-sensing pathway. In Saccharomyces cerevisiae, Mpk1 is involved in cell wall integrity and functions downstream of the protein kinase C homolog. In contrast, in S. pombe, Pmk1 may not act in a linear manner with respect to fission yeast protein kinase C homologs. Interestingly, however, these two pathways are not independent; instead, they regulate cell integrity in a coordinate manner.

scholarly journals The Yeast Protein Kinase C Cell Integrity Pathway Mediates Tolerance to the Antifungal Drug Caspofungin through Activation of Slt2p Mitogen-Activated Protein Kinase Signaling

2003 ◽  
Vol 2 (6) ◽  
pp. 1200-1210 ◽  
Author(s):  
Cristina Reinoso-Martín ◽  
Christoph Schüller ◽  
Manuela Schuetzer-Muehlbauer ◽  
Karl Kuchler
Keyword(s):  
Cell Wall ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Antifungal Drug ◽  
Mitogen Activated Protein Kinase ◽  
Cell Integrity ◽  
Cell Wall Synthesis ◽  
Kinase C ◽  
Mitogen Activated Protein ◽  
Yeast Genes

ABSTRACT The echinocandin caspofungin is a new antifungal drug that blocks cell wall synthesis through inhibition of β-(1-3)-glucan synthesis. Saccharomyces cerevisiae cells are able to tolerate rather high caspofungin concentrations, displaying high viability at low caspofungin doses. To identify yeast genes implicated in caspofungin tolerance, we performed a genome-wide microarray analysis. Strikingly, caspofungin treatment rapidly induces a set of genes from the protein kinase C (PKC) cell integrity signaling pathway, as well as those required for cell wall maintenance and architecture. The mitogen-activated protein kinase Slt2p is rapidly activated by phosphorylation, triggering signaling through the PKC pathway. Cells lacking genes such as SLT2, BCK1, and PKC1, as well as the caspofungin target gene, FKS1, display pronounced hypersensitivity, demonstrating that the PKC pathway is required for caspofungin tolerance. Notably, the cell surface integrity sensor Wsc1p, but not the sensors Wsc2-4p and Mid2p, is required for sensing caspofungin perturbations. The expression modulation of PKC target genes requires the transcription factor Rlm1p, which controls expression of several cell wall synthesis and maintenance genes. Thus, caspofungin-induced cell wall damage requires Wsc1p as a dedicated sensor to launch a protective response through the activated salvage pathway for de novo cell wall synthesis. Our results establish caspofungin as a specific activator of Slt2p stress signaling in baker's yeast.

scholarly journals Cdc37p Is Required for Stress-Induced High-Osmolarity Glycerol and Protein Kinase C Mitogen-Activated Protein Kinase Pathway Functionality by Interaction with Hog1p and Slt2p (Mpk1p)

2007 ◽  
Vol 6 (3) ◽  
pp. 521-532 ◽  
Author(s):  
Patricija Hawle ◽  
Danielle Horst ◽  
Jan Paul Bebelman ◽  
Xiao Xian Yang ◽  
Marco Siderius ◽  
...  
Keyword(s):  
Cell Wall ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Hog Pathway ◽  
High Osmolarity ◽  
High Osmolarity Glycerol ◽  
Kinase C ◽  
Mitogen Activated Protein

ABSTRACT The yeast Saccharomyces cerevisiae utilizes rapidly responding mitogen-activated protein kinase (MAPK) signaling cascades to adapt efficiently to a changing environment. Here we report that phosphorylation of Cdc37p, an Hsp90 cochaperone, by casein kinase 2 controls the functionality of two MAPK cascades in yeast. These pathways, the high-osmolarity glycerol (HOG) pathway and the cell integrity (protein kinase C) MAPK pathway, mediate adaptive responses to high osmotic and cell wall stresses, respectively. Mutation of the phosphorylation site Ser14 in Cdc37p renders cells sensitive to osmotic stress and cell wall perturbation by calcofluor white. We found that levels of the MAPKs Hog1p and Slt2p (Mpk1p) in cells are reduced in a cdc37-S14A mutant, and consequently downstream responses mediated by Hog1p and Slt2p are compromised. Furthermore, we present evidence that Hog1p and Slt2p both interact in a complex with Cdc37p in vivo, something that has not been reported previously. The interaction of Hsp90, Slt2p, and Hog1p with Cdc37p depends on the phosphorylation status of Cdc37p. In fact, our biochemical data show that the osmosensitive phenotype of the cdc37-S14A mutant is due to the loss of the interaction between Cdc37p, Hog1p, and Hsp90. Likewise, during cell wall stress, the interaction of Slt2p with Cdc37p and Hsp90 is crucial for Slt2p-dependent downstream responses, such as the activation of the transcription factor Rlm1p. Interestingly, phosphorylated Slt2p, but not phosphorylated Hog1p, has an increased affinity for Cdc37p. Together these observations suggest that Cdc37p acts as a regulator of MAPK signaling.

scholarly journals Novel Antifungal Compound Z-705 Specifically Inhibits Protein Kinase C of Filamentous Fungi

2019 ◽  
Vol 85 (10) ◽  
Author(s):  
Asumi Sugahara ◽  
Akira Yoshimi ◽  
Fumio Shoji ◽  
Tomonori Fujioka ◽  
Kiyoshi Kawai ◽  
...  
Keyword(s):  
Cell Wall ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Filamentous Fungi ◽  
Magnaporthe Grisea ◽  
Rice Blast Fungus ◽  
Mitogen Activated Protein Kinase ◽  
Content Type ◽  
Kinase C ◽  
Mitogen Activated Protein

ABSTRACTThe cell wall integrity signaling (CWIS) pathway is involved in fungal cell wall biogenesis. This pathway is composed of sensor proteins, protein kinase C (PKC), and the mitogen-activated protein kinase (MAPK) pathway, and it controls the transcription of many cell wall-related genes. PKC plays a pivotal role in this pathway; deficiencies in PkcA in the model filamentous fungusAspergillus nidulansand in MgPkc1p in the rice blast fungusMagnaporthe griseaare lethal. This suggests that PKC in filamentous fungi is a potential target for antifungal agents. In the present study, to search for MgPkc1p inhibitors, we carried outin silicoscreening by three-dimensional (3D) structural modeling and performed growth inhibition tests forM. griseaon agar plates. From approximately 800,000 candidate compounds, we selected Z-705 and evaluated its inhibitory activity against chimeric PKC expressed inSaccharomyces cerevisiaecells in which the kinase domain of nativeS. cerevisiaePKC was replaced with those of PKCs of filamentous fungi. Transcriptional analysis ofMLP1, which encodes a downstream factor of PKC inS. cerevisiae, and phosphorylation analysis of the mitogen-activated protein kinase (MAPK) Mpk1p, which is activated downstream of PKC, revealed that Z-705 specifically inhibited PKCs of filamentous fungi. Moreover, the inhibitory activity of Z-705 was similar to that of a well-known PKC inhibitor, staurosporine. Interestingly, Z-705 inhibited melanization induced by cell wall stress inM. grisea. We discuss the relationships between PKC and melanin biosynthesis.IMPORTANCEA candidate inhibitor of filamentous fungal protein kinase C (PKC), Z-705, was identified byin silicoscreening. A screening system to evaluate the effects of fungal PKC inhibitors was constructed inSaccharomyces cerevisiae. Using this system, we found that Z-705 is highly selective for filamentous fungal PKC in comparison withS. cerevisiaePKC. Analysis of theAGS1mRNA level, which is regulated by Mps1p mitogen-activated protein kinase (MAPK) via PKC, in the rice blast fungusMagnaporthe grisearevealed that Z-705 had a PKC inhibitory effect comparable to that of staurosporine. Micafungin induced hyphal melanization inM. grisea, and this melanization, which is required for pathogenicity ofM. grisea, was inhibited by PKC inhibition by both Z-705 and staurosporine. The mRNA levels of4HNR,3HNR, andSCD1, which are essential for melanization inM. grisea, were suppressed by both PKC inhibitors.

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