scholarly journals The Basic Leucine Zipper Domain Transcription Factor Atf1 Directly Controls Cdc13 Expression and Regulates Mitotic Entry Independently of Wee1 and Cdc25 in Schizosaccharomyces pombe

2014 ◽  
Vol 13 (6) ◽  
pp. 813-821 ◽  
Author(s):  
Sushobhana Bandyopadhyay ◽  
Isha Dey ◽  
Megalakshmi Suresh ◽  
Geetanjali Sundaram
Keyword(s):  
Transcription Factor ◽  
Schizosaccharomyces Pombe ◽  
Leucine Zipper ◽  
Mitogen Activated Protein Kinase ◽  
Cyclin Dependent Kinase ◽  
Basic Leucine Zipper ◽  
Content Type ◽  
Mitogen Activated Protein ◽  
Mitotic Cyclin ◽  
Approaches To Study

ABSTRACTProgression into mitosis is a major point of regulation in theSchizosaccharomyces pombecell cycle, and its proper control is essential for maintenance of genomic stability. Investigation of the G2/M progression event inS. pombehas revealed the existence of a complex regulatory process that is responsible for making the decision to enter mitosis. Newer aspects of this regulation are still being revealed. In this paper, we report the discovery of a novel mode of regulation of G2/M progression inS. pombe. We show that the mitogen-activated protein kinase (MAPK)-regulated transcription factor Atf1 is a regulator of Cdc13 (mitotic cyclin) transcription and is therefore a prominent player in the regulation of mitosis inS. pombe. We have used genetic approaches to study the effect of overexpression or deletion of Atf1 on the cell length and G2/M progression ofS. pombecells. Our results clearly show that Atf1 overexpression accelerates mitosis, leading to an accumulation of cells with shorter lengths. The previously known major regulators of entry into mitosis are the Cdc25 phosphatase and the Wee1 kinase, which modulate cyclin-dependent kinase (CDK) activity. The significantly striking aspect of our discovery is that Atf1-mediated G2/M progression is independent of both Cdc25 and Wee1. We have shown that Atf1 binds to the Cdc13 promoter, leading to activation of Cdc13 expression. This leads to enhanced nuclear localization of CDK Cdc2, thereby promoting the G2/M transition.

scholarly journals Ssp2 Binding Activates the Smk1 Mitogen-Activated Protein Kinase

2017 ◽  
Vol 37 (10) ◽  
Author(s):  
Chong Wai Tio ◽  
Gregory Omerza ◽  
Timothy Phillips ◽  
Hua Jane Lou ◽  
Benjamin E. Turk ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Chromosome Segregation ◽  
Kinase Activity ◽  
Specific Protein ◽  
Mitogen Activated Protein Kinase ◽  
Activation Loop ◽  
Cyclin Dependent Kinase ◽  
Content Type ◽  
Dual Specificity ◽  
Mitogen Activated Protein

ABSTRACT Smk1 is a meiosis-specific mitogen-activated protein kinase (MAPK) in Saccharomyces cerevisiae that couples spore morphogenesis to the completion of chromosome segregation. Similar to other MAPKs, Smk1 is controlled by phosphorylation of a threonine (T) and a tyrosine (Y) in its activation loop. However, it is not activated by a dual-specificity MAPK kinase. Instead, T207 in Smk1's activation loop is phosphorylated by the cyclin-dependent kinase (CDK)-activating kinase (Cak1), and Y209 is autophosphorylated in an intramolecular reaction that requires the meiosis-specific protein Ssp2. In this study, we show that Smk1 is catalytically inert unless it is bound by Ssp2. While Ssp2 binding activates Smk1 by a mechanism that is independent of activation loop phosphorylation, binding also triggers autophosphorylation of Y209 in Smk1, which, along with Cak1-mediated phosphorylation of T207, further activates the kinase. Autophosphorylation of Smk1 on Y209 also appears to modify the specificity of the MAPK by suppressing Y kinase and enhancing S/T kinase activity. We also found that the phosphoconsensus motif preference of Ssp2/Smk1 is more extensive than that of other characterized MAPKs. This study therefore defines a novel mechanism of MAPK activation requiring binding of an activator and also shows that MAPKs can be diversified to recognize unique phosphorylation motifs.

scholarly journals Mitogen-activated protein kinases associated sites of tobacco REPRESSION OF SHOOT GROWTH regulates its localization in plant cells

2021 ◽  
Author(s):  
Luyao Wang ◽  
Ying Gui ◽  
Bingye Yang ◽  
Fangjie Si ◽  
Jianhua Guo ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Plant Defense ◽  
Shoot Growth ◽  
Leucine Zipper ◽  
Intracellular Localization ◽  
Phosphorylation Site ◽  
Feedback Regulation ◽  
Mitogen Activated Protein Kinase ◽  
Basic Leucine Zipper ◽  
Mitogen Activated Protein

Plant defense and growth rely on multiple transcriptional factors (TFs). REPRESSION OF SHOOT GROWTH (RSG) is known as one of the important TFs in tobacco (Nicotiana tabacum) with a basic leucine zipper domain. RSG was involved in plant gibberellin feedback regulation by inducing the expression of key genes. The tobacco calcium-dependent protein kinase, CDPK1 was reported to interact with RSG and manipulate its intracellular localization by phosphorylating Ser-114 of RSG. Here, we identified tobacco mitogen-activated protein kinase 3 (NtMPK3) as a RSG interacted protein kinase. Mutation of predicted MAPK-associated phosphorylation site of RSG (Thr-30, Ser-74 and Thr-135) significantly altered the intracellular localization of NtMPK3-RSG interaction complex. Nuclear transport of RSG and its amino acids mutants (T30A and S74A) were observed after treated with plant defense elicitor peptide flg22 in 5 min, while the two mutated RSG swiftly relocalized in tobacco cytoplasm in 30 min. Moreover, triple points mutation of RSG (T30A/S74A/T135A) mimics constant unphosphorylated status, and predominantly localized in tobacco cytoplasm. RSG (T30A/S74A/T135A) showed no relocalization effect under the treatments of either flg22, B. cereus AR156 or GA3, and was impaired in its role as TFs. Our results suggest that MAPK associated phosphorylation sites of RSG regulate its localization in tobacco and constant unphosphorylation of RSG in Thr-30, Ser-74 and Thr-135 keeps RSG predominantly localized in cytoplasm.

scholarly journals Light Signaling Regulates Aspergillus niger Biofilm Formation by Affecting Melanin and Extracellular Polysaccharide Biosynthesis

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenjun Sun ◽  
Ying Yu ◽  
Jiao Chen ◽  
Bin Yu ◽  
Tianpeng Chen ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Aspergillus Niger ◽  
Signaling Pathway ◽  
Theoretical Basis ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Light Signaling ◽  
Content Type ◽  
Mitogen Activated Protein

ABSTRACT Light is an important signal source in nature, which regulates the physiological cycle, morphogenetic pathways, and secondary metabolites of fungi. As an external pressure on Aspergillus niger, light signaling transmits stress signals into the cell via the mitogen-activated protein kinase (MAPK) signaling pathway. Studying the effect of light on the biofilm of A. niger will provide a theoretical basis for light in the cultivation of filamentous fungi and industrial applications. Here, the characterization of A. niger biofilm under different light intensities confirmed the effects of light signaling. Our results indicated that A. niger intensely accumulated protective mycelial melanin under light illumination. We also discovered that the RlmA transcription factor in the MAPK signaling pathway is activated by light signaling to promote the synthesis of melanin, chitin, and other exopolysaccharides. However, the importance of melanin to A. niger biofilm is rarely reported; therefore, we knocked out key genes of the melanin biosynthetic pathway—Abr1 and Ayg1. Changes in hydrophobicity and electrostatic forces resulted in the decrease of biofilm caused by the decrease of melanin in mutants. IMPORTANCE As an important industrial filamentous fungus, Aspergillus niger can perceive light. The link between light signaling and A. niger biofilm is worthy of further study since reports are lacking in this area. This study found that light signaling promotes biofilm production in A. niger, wherein melanin plays an important role. It was further discovered that the RlmA transcription factor in the mitogen-activated protein kinase (MAPK) signaling pathway was mediated by light signaling to promote the synthesis of melanin and extracellular polysaccharides. These findings set the stage for light signal regulation of biofilm in filamentous fungi and provide a theoretical basis for the development of a new light-controlled biofilm method to improve biofilm-based industrial fermentation.

scholarly journals Suppressors of a Saccharomyces cerevisiae pkc1 mutation identify alleles of the phosphatase gene PTC1 and of a novel gene encoding a putative basic leucine zipper protein.

Genetics ◽  
1995 ◽  
Vol 141 (4) ◽  
pp. 1275-1285 ◽  
Author(s):  
K N Huang ◽  
L S Symington
Keyword(s):  
Protein Kinase ◽  
Leucine Zipper ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Gene Encoding ◽  
Basic Leucine Zipper ◽  
Mapk Cascades ◽  
Synthetically Lethal

Abstract The PKC1 gene product, protein kinase C, regulates a mitogen-activated protein kinase (MAPK) cascade, which is implicated in cell wall metabolism. Previously, we identified the pkc1-4 allele in a screen for mutants with increased rates of recombination, indicating that PKC1 may also regulate DNA metabolism. The pkc1-4 allele also conferred a temperature-sensitive (ts) growth defect. Extragenic suppressors were isolated that suppress both the ts and hyperrecombination phenotypes conferred by the pkc1-4 mutation. Eight of these suppressors for into two complementation groups, designated KCS1 and KCS2. KCS1 was cloned and found to encode a novel protein with homology to the basic leucine zipper family of transcription factors. KCS2 is allelic with PTC1, a previously identified type 2C serine/threonine protein phosphatase. Although mutation of either KCS1 or PTC1 causes little apparent phenotype, the kcs1 delta ptc1 delta double mutant fails to grow at 30 degrees. Furthermore, the ptc1 deletion mutation is synthetically lethal in combination with a mutation in MPK1, which encodes a MAPK homologue proposed to act in the PKC1 pathway. Because PTC1 was initially isolated as a component of the Hog1p MAPK pathway, it appears that these two MAPK cascades share a common regulatory feature.

scholarly journals Activation of a Novel Transcription Factor through Phosphorylation by WIPK, a Wound-Induced Mitogen-Activated Protein Kinase in Tobacco Plants

2005 ◽  
Vol 139 (1) ◽  
pp. 127-137 ◽  
Author(s):  
Yun-Kiam Yap ◽  
Yutaka Kodama ◽  
Frank Waller ◽  
Kwi Mi Chung ◽  
Hirokazu Ueda ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Tobacco Plants ◽  
Mitogen Activated Protein

scholarly journals Role for the Ran Binding Protein, Mog1p, in Saccharomyces cerevisiae SLN1-SKN7 Signal Transduction

2004 ◽  
Vol 3 (6) ◽  
pp. 1544-1556 ◽  
Author(s):  
Jade Mei-Yeh Lu ◽  
Robert J. Deschenes ◽  
Jan S. Fassler
Keyword(s):  
Signal Transduction ◽  
Transcription Factor ◽  
Osmotic Stress ◽  
Kinase Activity ◽  
Mitogen Activated Protein Kinase ◽  
Osmotic Response ◽  
Mitogen Activated Protein ◽  
Kinase Pathway

ABSTRACT Yeast Sln1p is an osmotic stress sensor with histidine kinase activity. Modulation of Sln1 kinase activity in response to changes in the osmotic environment regulates the activity of the osmotic response mitogen-activated protein kinase pathway and the activity of the Skn7p transcription factor, both important for adaptation to changing osmotic stress conditions. Many aspects of Sln1 function, such as how kinase activity is regulated to allow a rapid response to the continually changing osmotic environment, are not understood. To gain insight into Sln1p function, we conducted a two-hybrid screen to identify interactors. Mog1p, a protein that interacts with the yeast Ran1 homolog, Gsp1p, was identified in this screen. The interaction with Mog1p was characterized in vitro, and its importance was assessed in vivo. mog1 mutants exhibit defects in SLN1-SKN7 signal transduction and mislocalization of the Skn7p transcription factor. The requirement for Mog1p in normal localization of Skn7p to the nucleus does not fully account for the mog1-related defects in SLN1-SKN7 signal transduction, raising the possibility that Mog1p may play a role in Skn7 binding and activation of osmotic response genes.

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