IFIBYNE   05513
INSTITUTO DE FISIOLOGIA, BIOLOGIA MOLECULAR Y NEUROCIENCIAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
INTEGRATING SIGNALS: ENVIROMENT LINKS MAPK PATHWAYS IN S. cerevisiae
Autor/es:
BALTANAS, R; COLMAN-LERNER A; HOHMANN, S
Lugar:
Puerto Madryn, Chubut
Reunión:
Congreso; 46 Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2010
Resumen:
Cells must integrate information from multiple external inputs to
respond appropriately. Here, we study the interaction between the
pheromone response (PR) and high osmolarity glycerol (HOG)
pathways using quantitative fluorescent cytometry and western
blots. Despite sharing some of their components, these MAPK
cascades show no cross-activation when stimulated individually.
However, a high osmolarity shock to cells pre-exposed to
pheromone, leads to a rapid dephosphorylation of the PR MAPK,
which lasts for the duration of HOG activation. Surprisingly,
addition of pheromone to cells adapted to high osmolarity causes
persistent activation of HOG at the level of phosphorylation of the
MAPK Hog1, its nuclear translocation and induced transcription.
Our data suggest that the PR activates HOG by a two branched
mechanism: a) opening the glyceroporin Fps1, leading to reduction
of internal turgor pressure, and b) activation of Rgc1 (Regulator of
Glycerol Channel 1), required for HOG dependent transcription.
This hypothesis is supported by a) the observation that wt cells
adapted to 1M glycerol (instead of sorbitol) or Dfps1 cells do not
phosphorylate Hog1 and b) Drgc1 cells do phosphorylate Hog1 but
fail to induce gene expression. Finally, we found the activation of
HOG by pheromone is relevant, since its disruption leads to
significantly slower turgor pressure recovery from an osmotic
shock