PKA ROLE IN TRANSLATIONAL RESPONSE TO HEAT STRESS IN Saccharomyces cerevisiae

CLARA SOLARI; CARLA BARRAZA; PAULA PORTELA

Congreso; LII Reunión Anual SAIB; 2016

In Saccharomyces cerevisiae the cAMP dependent Protein Kinase (PKA) is involved in multiple steps of translation regulation in response to nutrient availability. PKA is a hetero-tetramer composed of two regulatory subunits encoded by BCY1 gene, and two catalytic subunits encoded by three genes, TPK1, TPK2 and TPK3. Previously, we demonstrated that mild heat stress induces the aggregation of Tpk3 and 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. Here, we analyse mRNP dynamics, translational arrest and translational fitness of CYC1, HSP42, HSP30 and ENO2 genes; whose tranlational fitness, 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 translational hypersensitivity to heat stress. TPK3 deletion inhibits mRNP formation as well as translational arrest and affects the translational response of analyzed genes. Therefore, our results provide evidence that Tpk2 and Tpk3 would have opposite role on heat stress translational adaptation.