scholarly journals Identification and characterization of an ABA-activated MAP kinase cascade inArabidopsis thaliana

2015 ◽  
Vol 82 (2) ◽  
pp. 232-244 ◽  
Author(s):  
Agyemang Danquah ◽  
Axel de Zélicourt ◽  
Marie Boudsocq ◽  
Jorinde Neubauer ◽  
Nicolas Frei dit Frey ◽  
...  
Genetics ◽  
1999 ◽  
Vol 153 (2) ◽  
pp. 763-771 ◽  
Author(s):  
Young-Mi Lim ◽  
Kimiko Nishizawa ◽  
Yoshimi Nishi ◽  
Leo Tsuda ◽  
Yoshihiro H Inoue ◽  
...  

Abstract Genetic and molecular characterization of the dominant suppressors of D-rafC110 on the second chromosome identified two gain-of-function alleles of rolled (rl), which encodes a mitogen-activated protein (MAP) kinase in Drosophila. One of the alleles, rlSu23, was found to bear the same molecular lesion as rlSem, which has been reported to be dominant female sterile. However, rlSu23 and the current stock of rlSem showed only a weak dominant female sterility. Detailed analyses of the rl mutations demonstrated moderate dominant activities of these alleles in the Torso (Tor) signaling pathway, which explains the weak dominant female sterility observed in this study. The dominant rl mutations failed to suppress the terminal class maternal-effect mutations, suggesting that activation of Rl is essential, but not sufficient, for Tor signaling. Involvement of rl in cell proliferation was also demonstrated by clonal analysis. Branching and integration of signals in the MAP kinase cascade is discussed.


Genetics ◽  
1997 ◽  
Vol 147 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Kathrin Schrick ◽  
Barbara Garvik ◽  
Leland H Hartwell

Abstract The mating process in yeast has two distinct aspects. One is the induction and activation of proteins required for cell fusion in response to a pheromone signal; the other is chemotropism, i.e., detection of a pheromone gradient and construction of a fusion site available to the signaling cell. To determine whether components of the signal transduction pathway necessary for transcriptional activation also play a role in chemotropism, we examined strains with null mutations in components of the signal transduction pathway for diploid formation, prezygote formation and the chemotropic process of mating partner discrimination when transcription was induced downstream of the mutation. Cells mutant for components of the mitogen-activated protein (MAP) kinase cascade (ste5, ste20, ste11, ste7 or fus3 kss1) formed diploids at a frequency 1% that of the wild-type control, but formed prezygotes as efficiently as the wild-type control and showed good mating partner discrimination, suggesting that the MAP kinase cascade is not essential for chemotropism. In contrast, cells mutant for the receptor (ste2) or the β or γ subunit (ste4 and stel8) of the G protein were extremely defective in both diploid and prezygote formation and discriminated poorly between signaling and nonsignaling mating partners, implying that these components are important for chemotropism.


Genetics ◽  
1998 ◽  
Vol 150 (4) ◽  
pp. 1407-1417 ◽  
Author(s):  
Simon J Dowell ◽  
Anne L Bishop ◽  
Susan L Dyos ◽  
Andrew J Brown ◽  
Malcolm S Whiteway

Abstract The mating pathway of Saccharomyces cerevisiae is widely used as a model system for G protein-coupled receptor-mediated signal transduction. Following receptor activation by the binding of mating pheromones, G protein βγ subunits transmit the signal to a MAP kinase cascade, which involves interaction of Gβ (Ste4p) with the MAP kinase scaffold protein Ste5p. Here, we identify residues in Ste4p required for the interaction with Ste5p. These residues define a new signaling interface close to the Ste20p binding site within the Gβγ coiled-coil. Ste4p mutants defective in the Ste5p interaction interact efficiently with Gpa1p (Gα) and Ste18p (Gγ) but cannot function in signal transduction because cells expressing these mutants are sterile. Ste4 L65S is temperature-sensitive for its interaction with Ste5p, and also for signaling. We have identified a Ste5p mutant (L196A) that displays a synthetic interaction defect with Ste4 L65S, providing strong evidence that Ste4p and Ste5p interact directly in vivo through an interface that involves hydrophobic residues. The correlation between disruption of the Ste4p-Ste5p interaction and sterility confirms the importance of this interaction in signal transduction. Identification of the Gβγ coiled-coil in Ste5p binding may set a precedent for Gβγ-effector interactions in more complex organisms.


2012 ◽  
Vol 11 (3) ◽  
pp. 253-263 ◽  
Author(s):  
Zhibin Zhang ◽  
Yaling Wu ◽  
Minghui Gao ◽  
Jie Zhang ◽  
Qing Kong ◽  
...  

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