CELL WALL INTEGRITY AND TRANSCRIPTIONAL REGULATION OF TPK1 SUBUNIT OF PKA FROM Saccharomyces cerevisiae

CAÑONERO, LUCIANA; PAUTASSO, CONSTANZA; ROSSI, SILVIA

Rosario

Congreso; L Reunión Anual de la Sociedad Argentina de Bioquímica y Biología Molecular; 2014

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

A signal transduction cascade, the CWI (cell wall integrity) pathway of Saccharomyces cerevisiae contains cell wall stress sensors that lead to the activation of a mitogen-activated protein kinase (MAPK) cascade. Signaling through the MAPK cascade leads to expression of transcription factors that facilitate biosynthesis of cell wall components andactin organization. To manage the diverse stress conditions, the CWI pathway cross talks with other pathways or proteins, such as the protein kinase A pathway. PKA is composed of catalytic and regulatory subunits. The catalytic subunits are encoded by TPK1, TPK2 and TPK3 genes. We analyzed the regulation of TPK1 expression during heat stress by the CWI pathway. Wsc1-3 functions as the cell stress sensors to activate the CWI pathway in response to heat shock and activate the MAPK cascade. Using β-galactosidase reporter and quantification of mRNA by qRT-PCRwe demonstrate that the three isoforms of the Wsc receptor are not redundant for heat-shock response. Wsc1 upregulates and Wsc3 downregulates TPK1 expression. Further, using different deletion strains, the involvement of MAPK kinase pathway in TPK1 expression regulation was demonstrated, although the results also show that other parallel pathway should be also involved in this regulation. The results indicate that exists a cross talk among MAPK and PKA pathway during heat shock.