The cell surface protein gene ecm33+ is a target of the two transcription factors Atf1 and Mbx1 and negatively regulates Pmk1 MAPK cell integrity signaling in fission yeast.
The highly conserved fission yeast Pmk1 MAPK pathway plays a key role in cell integrity by regulating Atf1, which belongs to the ATF/cAMP-responsive element-binding (CREB) protein family. We identified and characterized ecm33(+), which encodes a glycosyl-phosphatidylinositol (GPI)-anchored cell surface protein as a transcriptional target of Pmk1 and Atf1. We demonstrated that the gene expression of Ecm33 is regulated by two transcription factors Atf1 and a MADS-box-type transcription factor Mbx1. We identified a putative ATF/CREB-binding site and an RLM1-binding site in the ecm33(+) promoter region and monitored the transcriptional activity of Atf1 or Mbx1 in living cells using a destabilized luciferase reporter gene fused to three tandem repeats of the CRE and six tandem repeats of the Rlm1-binding sequence, respectively. These reporter genes reflect the activation of the Pmk1 pathway by various stimuli, thereby enabling the real-time monitoring of the Pmk1 cell integrity pathway. Notably, the Deltaecm33 cells displayed hyperactivation of the Pmk1 signaling together with hypersensitivity to Ca(2+) and an abnormal morphology, which were almost abolished by simultaneous deletion of the components of the Rho2/Pck2/Pmk1 pathway. Our results suggest that Ecm33 is involved in the negative feedback regulation of Pmk1 cell integrity signaling and is linked to cellular Ca(2+) signaling.
Takada
Hirofumi
H
Laboratory of Molecular Pharmacogenomics, Laboratory of Molecular and Cellular Biology, and Laboratory of Bioinformatics, School of Pharmaceutical Sciences, Kinki University, Higashi-Osaka, 577-8502, Japan.
Nishida
Aiko
A
Domae
Mitsuhiro
M
Kita
Ayako
A
Yamano
Yuki
Y
Uchida
Atsushi
A
Ishiwata
Shunji
S
Fang
Yue
Y
Zhou
Xin
X
Masuko
Takashi
T
Kinoshita
Mitsuhiro
M
Kakehi
Kazuaki
K
Sugiura
Reiko
R
D051697:Activating Transcription Factor 1 / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D017930:Genes, Reporter; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012568:Schizosaccharomyces / Q000166:cytology / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*
D051697:Activating Transcription Factor 1; C000591535:ECM33 protein, S pombe; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D029702:Schizosaccharomyces pombe Proteins; D020928:Mitogen-Activated Protein Kinases; C516338:Pmk1 protein, S pombe; D002118:Calcium