The role of PKA in the translational response to heat stress in Saccharomyces cerevisiae

CARLA BARRAZA; CLARA SOLARI; IRINA MARCOVICH; CHRISTOPHER KERSHAW; FIORELLA GALELLO; SILVIA ROSSI; MARK ASHE; PAULA PORTELA

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2017

1932-6203

Cellular responses to stress stem from a variety of different mechanisms, including transla-tion arrest and relocation of the translationally repressed mRNAs to ribonucleoprotein parti-cles like stress granules (SGs) and processing bodies (PBs). Here, we examine the role ofPKA in the S. cerevisiae heat shock response. Under mild heat stress Tpk3 aggregates andpromotes aggregation of eIF4G, Pab1 and eIF4E, whereas severe heat stress leads to theformation of PBs and SGs that contain both Tpk2 and Tpk3 and a larger 48S translation initi-ation complex. Deletion of TPK2 or TPK3 impacts upon the translational response to heatstress of several mRNAs including CYC1, HSP42, HSP30 and ENO2. TPK2 deletion leadsto a robust translational arrest, an increase in SGs/PBs aggregation and translational hyper-sensitivity to heat stress, whereas TPK3 deletion represses SGs/PBs formation, transla-tional arrest and response for the analyzed mRNAs. Therefore, this work provides evidenceindicating that Tpk2 and Tpk3 have opposing roles in translational adaptation during heatstress, and highlight how the same signaling pathway can be regulated to generate strikinglydistinct physiological outputs.