scholarly journals PsSAK1, a Stress-Activated MAP Kinase of Phytophthora sojae, Is Required for Zoospore Viability and Infection of Soybean

2010 ◽  
Vol 23 (8) ◽  
pp. 1022-1031 ◽  
Author(s):  
Aining Li ◽  
Yonglin Wang ◽  
Kai Tao ◽  
Suomeng Dong ◽  
Qian Huang ◽  
...  
Keyword(s):  
Hyphal Growth ◽  
Polymerase Chain Reaction Analysis ◽  
Phytophthora Sojae ◽  
Mitogen Activated Protein Kinase ◽  
Pleckstrin Homology Domain ◽  
Evolutionarily Conserved ◽  
Mitogen Activated Protein ◽  
Important Regulator ◽  
Soybean Leaves ◽  
Germ Tubes

Mitogen-activated protein kinase (MAPK) pathways are universal and evolutionarily conserved signal transduction modules in all eukaryotic cells. In this study, PsSAK1, which encodes a stress-activated MAPK of Phytophthora sojae, was identified. PsSAK1 is highly conserved in oomycetes, and it represents a novel group of MAPK due to its pleckstrin homology domain. Reverse-transcription polymerase chain reaction analysis showed that PsSAK1 expression was upregulated in zoospores and cysts and during early infection. In addition, its expression was induced by osmotic and oxidative stress mediated by NaCl and H2O2, respectively. To elucidate the function, the expression of PsSAK1 was silenced using stable transformation of P. sojae. The silencing of PsSAK1 did not impair hyphal growth, sporulation, or oospore production but severely hindered zoospore development, in that the silenced strains showed quicker encystment and a lower germination ratio than the wild type. PsSAK1-silenced mutants produced much longer germ tubes and could not colonize either wounded or unwounded soybean leaves. Our results indicate that PsSAK1 is an important regulator of zoospore development and pathogenicity in P. sojae.

scholarly journals Cell Biology of Conidial Anastomosis Tubes in Neurospora crassa

2005 ◽  
Vol 4 (5) ◽  
pp. 911-919 ◽  
Author(s):  
M. Gabriela Roca ◽  
Jochen Arlt ◽  
Chris E. Jeffree ◽  
Nick D. Read
Keyword(s):  
Neurospora Crassa ◽  
Optical Tweezers ◽  
Cell Biology ◽  
Transmembrane Protein ◽  
Mitogen Activated Protein Kinase ◽  
Cellular Element ◽  
Hyphal Fusion ◽  
Self Recognition ◽  
Mitogen Activated Protein ◽  
Germ Tubes

ABSTRACT Although hyphal fusion has been well documented in mature colonies of filamentous fungi, it has been little studied during colony establishment. Here we show that specialized hyphae, called conidial anastomosis tubes (CATs), are produced by all types of conidia and by conidial germ tubes of Neurospora crassa. The CAT is shown to be a cellular element that is morphologically and physiologically distinct from a germ tube and under separate genetic control. In contrast to germ tubes, CATs are thinner, shorter, lack branches, exhibit determinate growth, and home toward each other. Evidence for an extracellular CAT inducer derived from conidia was obtained because CAT formation was reduced at low conidial concentrations. A cr-1 mutant lacking cyclic AMP (cAMP) produced CATs, indicating that the inducer is not cAMP. Evidence that the transduction of the CAT inducer signal involves a putative transmembrane protein (HAM-2) and the MAK-2 and NRC-1 proteins of a mitogen-activated protein kinase signaling pathway was obtained because ham-2, mak-2, and nrc-1 mutants lacked CATs. Optical tweezers were used in a novel experimental assay to micromanipulate whole conidia and germlings to analyze chemoattraction between CATs during homing. Strains of the same and opposite mating type were shown to home toward each other. The cr-1 mutant also underwent normal homing, indicating that cAMP is not the chemoattractant. ham-2, mak-2, and nrc-1 macroconidia did not attract CATs of the wild type. Fusion between CATs of opposite mating types was partially inhibited, providing evidence of non-self-recognition prior to fusion. Microtubules and nuclei passed through fused CATs.

scholarly journals A Yeast STE11 Homologue CoMEKK1 Is Essential for Pathogenesis-Related Morphogenesis in Colletotrichum orbiculare

2010 ◽  
Vol 23 (12) ◽  
pp. 1563-1572 ◽  
Author(s):  
Ayumu Sakaguchi ◽  
Gento Tsuji ◽  
Yasuyuki Kubo
Keyword(s):  
Signal Transduction ◽  
Fluorescent Protein ◽  
Intracellular Localization ◽  
Active Form ◽  
Hyphal Growth ◽  
Mitogen Activated Protein Kinase ◽  
Colletotrichum Orbiculare ◽  
Pathogenesis Related ◽  
Mitogen Activated Protein ◽  
Green Fluorescent

Several signal transduction pathways, including mitogen-activated protein kinase (MAPK) pathways, are involved in appressorium development in Colletotrichum orbiculare, the causal agent of cucumber anthracnose disease. In this study, CoMEKK1, a yeast MAPK kinases (MAPKK) kinase STE11 homolog, was identified as a disrupted gene in an Agrobacterium tumefaciens-mediated transformation mutant. The phenotype of comekk1 disruptant was similar to that of cmk1, a Saccharomyces cerevisiae Fus3/Kss1 MAPK homolog mutant. Moreover, comekk1 and cmk1 mutants were sensitive to high osmotic and salinity stresses, indicating that Comekk1p/Cmk1p signal transduction is involved in stress tolerance. The transformants of the wild type and the comekk1 mutant expressing a constitutively active form of the CoMEKK1 showed slower hyphal growth and abnormal appressorium formation, whereas those of the cmk1 disruptant did not. A Cmk1p-green fluorescent protein (GFP) intracellular localization experiment indicated that nuclear localization of the Cmk1p-GFP fusion protein induced by salt stress was diminished in comekk1 mutants. These results indicate that Comekk1p functions upstream of Cmk1p.

scholarly journals Identification of Cdc37 as a Novel Regulator of the Stress-Responsive Mitogen-Activated Protein Kinase

2003 ◽  
Vol 23 (15) ◽  
pp. 5132-5142 ◽  
Author(s):  
Hisashi Tatebe ◽  
Kazuhiro Shiozaki
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Inflammatory Responses ◽  
Cellular Level ◽  
Mitogen Activated Protein Kinase ◽  
Cellular Survival ◽  
Evolutionarily Conserved ◽  
Mitogen Activated Protein ◽  
Extracellular Stimuli ◽  
The Stability

ABSTRACT Eukaryotic cells utilize multiple mitogen-activated protein kinases (MAPKs) to transmit various extracellular stimuli to the nucleus. A subfamily of MAPKs that mediates environmental stress stimuli is also called stress-activated protein kinase (SAPK), which has crucial roles in cellular survival under stress conditions as well as inflammatory responses. Here we report that Cdc37, an evolutionarily conserved kinase-specific chaperone, is a positive regulator of Spc1 SAPK in the fission yeast Schizosaccharomyces pombe. Through a genetic screen, we have identified cdc37 as a mutation that compromises signaling through Spc1 SAPK. The Cdc37 protein physically interacts with Spc1, and the cdc37 mutation affects both the cellular level of the Spc1 protein and stress-induced Spc1 phosphorylation by Wis1 MAPK kinase (MAPKK). Consistently, expression of the stress response genes regulated by the Spc1 pathway is compromised in cdc37 mutant cells. On the other hand, a mutation in Hsp90, which often cooperates with Cdc37 in chaperoning protein kinases, does not affect Spc1 SAPK. These results suggest that Spc1 SAPK is a novel client protein for the Cdc37 chaperone, and the Cdc37 function is important to maintain the stability of the Spc1 protein and to facilitate stress signaling from Wis1 MAPKK to Spc1 SAPK.

scholarly journals Novel Mitogen-Activated Protein Kinase MpkC of Aspergillus fumigatus Is Required for Utilization of Polyalcohol Sugars

2006 ◽  
Vol 5 (11) ◽  
pp. 1934-1940 ◽  
Author(s):  
Guadalupe Reyes ◽  
Angela Romans ◽  
C. Kim Nguyen ◽  
Gregory S. May
Keyword(s):  
Carbon Source ◽  
Aspergillus Fumigatus ◽  
Hyphal Growth ◽  
Mitogen Activated Protein Kinase ◽  
Deletion Mutants ◽  
Mrna Levels ◽  
Hypertonic Stress ◽  
Mitogen Activated Protein ◽  
Stress Oxidative ◽  
Mapk Gene

ABSTRACT The genome of Aspergillus fumigatus has four genes that encode mitogen-activated protein kinases (MAPKs), sakA/hogA, mpkA, mpkB, and mpkC. The functions of the MpkB and MpkC MAPKs are unknown for A. fumigatus and the closely related and genetically amenable species Aspergillus nidulans. mpkC deletion mutants of A. fumigatus were made and their phenotypes characterized. The mpkC deletion mutants were viable and had normal conidial germination and hyphal growth on minimal or complete media. This is in contrast to deletion mutants with deletions in the closely related MAPK gene sakA/hogA that we previously reported had a nitrogen source-dependent germination phenotype. Similarly, the growth of the mpkC deletion mutants was wild type on high-osmolarity medium. Consistent with these two MAP kinase genes regulating different cellular responses, we determined that the mpkC deletion mutants were unable to grow on minimal medium with sorbitol or mannitol as the sole carbon source. This result implicates MpkC signaling in carbon source utilization. Changes in mRNA levels for sakA and mpkC were measured in response to hypertonic stress, oxidative stress, and a shift from glucose to sorbitol to determine if there was overlap in the SakA and MpkC signaling pathways. These studies demonstrated that SakA- and MpkC-dependent patterns of change in mRNA levels are distinct and have minimal overlap in response to these environmental stresses.

scholarly journals The p38 Mitogen-Activated Protein Kinase Regulates 11β-Hydroxysteroid Dehydrogenase Type 2 (11β-HSD2) Expression in Human Trophoblast Cells through Modulation of 11β-HSD2 Messenger Ribonucleic Acid Stability

Endocrinology ◽  
2009 ◽  
Vol 150 (9) ◽  
pp. 4278-4286 ◽  
Author(s):  
Anju Sharma ◽  
Haiyan Guan ◽  
Kaiping Yang
Keyword(s):  
P38 Mapk ◽  
Hydroxysteroid Dehydrogenase ◽  
Mitogen Activated Protein Kinase ◽  
Trophoblast Cells ◽  
Human Trophoblast ◽  
Messenger Ribonucleic Acid ◽  
Mitogen Activated Protein ◽  
Important Regulator ◽  
Interfering Rna

Abstract The placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2; encoded by the HSD11B2 gene) has emerged as a key player in controlling fetal development, but its regulation is incompletely understood. Here we identified p38 MAPK as an important regulator of placental 11β-HSD2. We showed that inhibition of p38 MAPK with the pharmacological inhibitor SB202190 led to an approximately 50% reduction in 11β-HSD2 activity, protein, and mRNA in primary human placental trophoblast cells. Furthermore, the effect of SB202190 was confirmed by the use of two additional p38 inhibitors, SB203580 and SB220025. In addition, SB202190 decreased the half-life of 11β-HSD2 mRNA without altering the HSD11B2 promoter activity, indicating that p38 MAPK regulates placental 11β-HSD2 expression through modulation of 11β-HSD2 mRNA stability. Importantly, small interfering RNA-mediated knockdown of p38α caused a 50% reduction in 11β-HSD2 activity, suggesting that p38α is the primary p38 isoform involved. Taken together, these findings suggest a novel pathway controlling placental 11β-HSD2 expression resulting from the activation of p38 MAPK. Given that p38α is abundantly expressed in the human placenta in which its function is largely unknown, our present study also reveals 11β-HSD2 as an important target through which p38α may regulate human placental function and consequently fetal growth and development.

scholarly journals Sin1-mediated mTOR signaling in cell growth, metabolism and immune response

2019 ◽  
Vol 6 (6) ◽  
pp. 1149-1162
Author(s):  
Chun Ruan ◽  
Xinxing Ouyang ◽  
Hongzhi Liu ◽  
Song Li ◽  
Jingsi Jin ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Current Knowledge ◽  
Mammalian Target Of Rapamycin ◽  
Adaptor Protein ◽  
Interaction Network ◽  
Mitogen Activated Protein Kinase ◽  
Cellular Functions ◽  
Evolutionarily Conserved ◽  
Mitogen Activated Protein ◽  
Growth Metabolism

Abstract The mammalian target of rapamycin (mTOR) is an evolutionarily conserved Ser/Thr protein kinase with essential cellular function via processing various extracellular and intracellular inputs. Two distinct multi-protein mTOR complexes (mTORC), mTORC1 and mTORC2, have been identified and well characterized in eukaryotic cells from yeast to human. Sin1, which stands for Sty1/Spc1-interacting protein1, also known as mitogen-activated protein kinase (MAPK) associated protein (MAPKAP)1, is an evolutionarily conserved adaptor protein. Mammalian Sin1 interacts with many cellular proteins, but it has been widely studied as an essential component of mTORC2, and it is crucial not only for the assembly of mTORC2 but also for the regulation of its substrate specificity. In this review, we summarize our current knowledge of the structure and functions of Sin1, focusing specifically on its protein interaction network and its roles in the mTOR pathway that could account for various cellular functions of mTOR in growth, metabolism, immunity and cancer.

scholarly journals The CfMK1 Gene Regulates Reproduction, Appressorium Formation, and Pathogenesis in a Pear Anthracnose-Causing Fungus

2022 ◽  
Vol 8 (1) ◽  
pp. 77
Author(s):  
Chaohui Li ◽  
Weibo Sun ◽  
Shulin Cao ◽  
Rongxian Hou ◽  
Xiaogang Li ◽  
...  
Keyword(s):  
Cell Wall ◽  
Germination Rate ◽  
Hyphal Growth ◽  
Pathogenic Fungi ◽  
Mitogen Activated Protein Kinase ◽  
Economic Losses ◽  
Deletion Mutants ◽  
Appressorium Formation ◽  
Mapk Cascades ◽  
Mitogen Activated Protein

Colletotrichum fructicola, the causal agent of pear anthracnose, causes significant annual economic losses. Mitogen-activated protein kinase (MAPK) cascades are highly conserved signal transduction pathways that play a crucial role in mediating cellular responses to environmental and host signals in plant pathogenic fungi. In this study, we identified an ortholog of the FUS3/KSS1-related MAPK gene, CfMK1, and characterized its function in C. fructicola. The Cfmk1 deletion mutants exhibited poorly developed aerial hyphae, autolysis, no conidial mass or perithecia on solid plates. However, the conidiation of the Cfmk1 mutant in PDB liquid medium was normal compared with that of the wild type (WT). Conidia of the Cfmk1 mutant exhibited a reduced germination rate on glass slides or plant surfaces. The Cfmk1 deletion mutants were unable to form appressoria and lost the capacity to penetrate plant epidermal cells. The ability of the Cfmk1 mutants to infect pear leaves and fruit was severely reduced. Moreover, RNA sequencing (RNA-seq) analysis of the WT and Cfmk1 mutant was performed, and the results revealed 1886 upregulated and 1554 downregulated differentially expressed genes (DEGs) in the mutant. The DEGs were significantly enriched in cell wall and pathogenesis terms, which was consistent with the defects of the Cfmk1 mutant in cell wall integrity and plant infection. Overall, our data demonstrate that CfMK1 plays critical roles in the regulation of aerial hyphal growth, asexual and sexual reproduction, autolysis, appressorium formation, and pathogenicity.

scholarly journals Schizosaccharomyces pombe Spk1 is a tyrosine-phosphorylated protein functionally related to Xenopus mitogen-activated protein kinase.

1993 ◽  
Vol 13 (10) ◽  
pp. 6427-6434 ◽  
Author(s):  
Y Gotoh ◽  
E Nishida ◽  
M Shimanuki ◽  
T Toda ◽  
Y Imai ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Schizosaccharomyces Pombe ◽  
Tyrosine Phosphorylation ◽  
Mitogen Activated Protein Kinase ◽  
Diploid Strain ◽  
Evolutionarily Conserved ◽  
Mitogen Activated Protein ◽  
Tyrosine Phosphorylated Protein ◽  
Higher Eukaryotes ◽  
Direct Activator

Mitogen-activated protein kinase (MAPK) and its direct activator, MAPK kinase (MAPKK), have been suggested to play a pivotal role in a variety of signal transduction pathways in higher eukaryotes. The fission yeast Schizosaccharomyces pombe carries a gene, named spk1, whose product is structurally related to vertebrate MAPK. Here we show that Spk1 is functionally related to Xenopus MAPK. (i) Xenopus MAPK partially complemented a defect in the spk1- mutant. An spk1- diploid strain could not sporulate, but one carrying Xenopus MAPK could. (ii) Both Spk1 and Xenopus MAPK interfered with sporulation if overexpressed in S. pombe cells. (iii) Spk1 underwent tyrosine phosphorylation as does Xenopus MAPK. Tyrosine phosphorylation of Spk1 appeared to be dependent upon mating signals because it occurred in homothallic cells but not in heterothallic cells. Furthermore, this phosphorylation was diminished in a byr1 disruptant strain, suggesting that spk1 lies downstream of byr1, which encodes a MAPKK homolog in S. pombe. Taken together, the MAPKK-MAPK cascade may be evolutionarily conserved in signaling pathways in yeasts and vertebrates.

scholarly journals Identification of 23-(S)-2-Amino-3-Phenylpropanoyl-Silybin as an Antiviral Agent for Influenza A Virus InfectionIn VitroandIn Vivo

2013 ◽  
Vol 57 (9) ◽  
pp. 4433-4443 ◽  
Author(s):  
Jian-Ping Dai ◽  
Li-Qi Wu ◽  
Rui Li ◽  
Xiang-Feng Zhao ◽  
Qian-Ying Wan ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Antiviral Agent ◽  
Screening Strategy ◽  
Mitogen Activated Protein Kinase ◽  
Content Type ◽  
Iκb Kinase ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Important Regulator

ABSTRACTIt has been reported that autophagy is involved in the replication of many viruses. In this study, we screened 89 medicinal plants, using an assay based on the inhibition of the formation of the Atg12-Atg5/Atg16 heterotrimer, an important regulator of autophagy, and selectedSilybum marianumL. for further study. An antiviral assay indicated that silybin (S0), the major active compound ofS. marianumL., can inhibit influenza A virus (IAV) infection. We later synthesized 5 silybin derivatives (S1 through S5) and found that 23-(S)-2-amino-3-phenylpropanoyl-silybin (S3) had the best activity. When we compared the polarities of the substituent groups, we found that the hydrophobicity of the substituent groups was positively correlated with their activities. We further studied the mechanisms of action of these compounds and determined that S0 and S3 also inhibited both the formation of the Atg12-Atg5/Atg16 heterotrimer and the elevated autophagy induced by IAV infection. In addition, we found that S0 and S3 could inhibit several components induced by IAV infection, including oxidative stress, the activation of extracellular signal-regulated kinase (ERK)/p38 mitogen-activated protein kinase (MAPK) and IκB kinase (IKK) pathways, and the expression of autophagic genes, especially Atg7 and Atg3. All of these components have been reported to be related to the formation of the Atg12-Atg5/Atg16 heterotrimer, which might validate our screening strategy. Finally, we demonstrated that S3 can significantly reduce influenza virus replication and the associated mortality in infected mice. In conclusion, we identified 23-(S)-2-amino-3-phenylpropanoyl-silybin as a promising inhibitor of IAV infection.

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