Transcription factors under the control of the yeast Hog1 MAPK

dc.contributor
Universitat Pompeu Fabra. Departament de Ciències Experimentals i de la Salut
dc.contributor.author
Casadomé Burriel, Laura
dc.date.accessioned
2011-04-12T16:27:58Z
dc.date.available
2005-09-05
dc.date.issued
2005-03-01
dc.date.submitted
2005-09-05
dc.identifier.isbn
8468938397
dc.identifier.uri
http://www.tdx.cat/TDX-0905105-110906
dc.identifier.uri
http://hdl.handle.net/10803/7086
dc.description.abstract
Yeast cells are exposed to a wide variety of environment stresses, among them changes in the osmotic conditions. An osmolar upshift leads to fast loose of intracellular water, so living cells have developed mechanisms to counteract this lost. In Saccharomyces cerevisiae changes in the osmotic conditions are sensed by the HOG pathway. The HOG pathway is a MAPK signalling pathway and the functional homolog of the stress activated MAPK JNK MAPK and p38 present in mammals. Because there is a high degree of conservation of these cascades, the HOG pathway is a good model to study osmotic adaptation processes.<br/>Recent reports have shown that the Hog1 MAPK can regulate several processes such as cell cycle control, metabolic adaptation or regulation of gene expression.<br/>At the beginning of this work, the mechanisms by which the Hog1 MAPK was controlling gene expression were unclear because transcription factors under the control of the MAPK were not well characterized. Our goal was the identification of new transcription factors under the control of the MAPK. Therefore, we designed a genetic screen and selected clones from a multicopy genomic library that were able to induce the expression of Hog1 dependent genes in non stress conditions. One of these clones was the SMP1 gene. Smp1 encodes for a MEF2-like transcription factor. Its overexpression induced the expression of osmoresponsive genes such as STL1, whereas smp1 cells were defective in their expression. smp1 cells showed reduced viability upon osmotic shock. Smp1-Hog1 interaction was checked by coprecipitation. Moreover, Smp1 was phosphorylated upon osmotic stress in a Hog1-dependent manner and in vitro phosphorylation experiments showed that Hog1 phosphorylated Smp1 at the C-terminal region. This phosphorylation was important for Smp1 osmoadaptation functions.<br/>Moreover Hog1 was implicated in cell adaptability to stationary phase through Smp1.<br/>On the other hand, microarrays studies showed that HXT1 hexose transporter was upregulated upon an osmotic shock in a Hog1 dependent manner. Expression of the HXT1 gene, which encodes a low affinity glucose transporter in Saccharomyces cerevisiae, is induced in response to glucose by the general glucose induction pathway, involving the Snf3/Rgt2 membrane glucose sensors, the SCF-Grr1 ubiquitination complex and the Rgt1 transcription factor. In addition to the glucose signalling pathway, we have found that, regulation of HXT1 expression also requires the HOG pathway. Deletion of components on both pathways results in impaired HXT1 expression. Genetic analyses identified Sko1 as the transcription factor under the control of Hog1 that was modulating HXT1 expression.<br/>Our studies here have shown that both Smp1 and Sko1 are transcription factors under the control of the MAPK.
eng
dc.format.mimetype
application/pdf
dc.language.iso
eng
dc.publisher
Universitat Pompeu Fabra
dc.rights.license
ADVERTIMENT. L'accés als continguts d'aquesta tesi doctoral i la seva utilització ha de respectar els drets de la persona autora. Pot ser utilitzada per a consulta o estudi personal, així com en activitats o materials d'investigació i docència en els termes establerts a l'art. 32 del Text Refós de la Llei de Propietat Intel·lectual (RDL 1/1996). Per altres utilitzacions es requereix l'autorització prèvia i expressa de la persona autora. En qualsevol cas, en la utilització dels seus continguts caldrà indicar de forma clara el nom i cognoms de la persona autora i el títol de la tesi doctoral. No s'autoritza la seva reproducció o altres formes d'explotació efectuades amb finalitats de lucre ni la seva comunicació pública des d'un lloc aliè al servei TDX. Tampoc s'autoritza la presentació del seu contingut en una finestra o marc aliè a TDX (framing). Aquesta reserva de drets afecta tant als continguts de la tesi com als seus resums i índexs.
dc.source
TDX (Tesis Doctorals en Xarxa)
dc.subject
factors de transcripció
dc.subject
saccharomyces cerevisiae
dc.subject
protein quinases
dc.subject
metabolism
dc.subject
transcription factors
dc.subject
metabolisme
dc.subject
proteïnes quinases
dc.subject
saccharomyces cerevisiae
dc.title
Transcription factors under the control of the yeast Hog1 MAPK
dc.type
info:eu-repo/semantics/doctoralThesis
dc.type
info:eu-repo/semantics/publishedVersion
dc.subject.udc
576
cat
dc.contributor.authoremail
laura.casadome@gmail.com
dc.contributor.director
Posas Garriga, Francesc
dc.contributor.director
Nadal Clanchet, Eulàlia de
dc.rights.accessLevel
info:eu-repo/semantics/openAccess
cat
dc.identifier.dl
B.40015-2005
dc.description.degree
Programa de doctorat en Biomedicina


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