PKA role in translational response to heat stress in Saccharomyces cerevisiae.

BARRAZA C; SOLARI C; MARCOVICH I; ROSSI S; ASHE M; PORTELA P

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2017

1932-6203

Cellular response to stress conditions using different mechanisms such as translation arrest and transient relocation of untranslated mRNAs to ribonucleic practicles (mRNPs) known as stress granules (SGs) and processing bodies (PBs). Previously, we demonstrate that cAMP dependent Protein Kinase (PKA) is involved in multiple steps of translation regulation in response to nutrient availability. In Saccharoymeces cerevisiae there is one gene that encodes for the regulatory subunit (BCY1) and three that encode for the catalytic isoforms (TPK1, TPK2 and TPK3). Here, we examine the role of PKA in heat shock response. In response to heat stress severity, nuclear-cytoplasmic relocalization of each PKA catalytic subunit was observed. Mild heat stress induces the aggregation of Tpk3 and promotes the aggregation of closed mRNA loop complexes into SGs. Severe heat stress leads to the formation of PBs and SGs that contain Tpk2 and Tpk3 and directs the accumulation and aggregation of the initiation translation complex 48S. Tpk1 showed mostly cytoplasmic localization. Analysis of mRNP dynamic, translational arrest and translational fitness of CYC1, HSP42, HSP30 and ENO2 gene whose tranlational fitness is regulated by heat stress showed that TPK3 or TPK2 deletion affects the translational response to severe heat stress. TPK2 deletion leads to strong translational arrest, an increment in mRNP agreggation and the translational hypersensitivity to heat stress. TPK3 deletion inhibits mRNP formation as well as translational arrest and affected the translational response of analyzed genes. Therefore, our results provide evidence that Tpk2 and Tpk3 would have opposite role on heat stress translational adaptation.