EXPRESSION REGULATION OF PROTEIN KINASE A SUBUNITS FROM Saccharomyces cerevisiae

CAÑONERO, LUCIANA; PAUTASSO, CONSTANZA; SIGAUT, LORENA I; ORTOLÁ, MARÍA CLARA; ROSSI, SILVIA

Paraná, Entre Ríos

Congreso; LIV Reunión Anual de la Sociedad Argentina de Bioquímica y Biología Molecular (SAIB); 2018

SAIB

In S.cerevisiae the protein kinase A (PKA) is a tetramer composed of catalytic subunits, TPK1, TPK2, TPK3 and a regulatory subunit, BCY1. PKA controls several cellular events in response to different stimuli. The specificity in cAMP-PKA signaling is maintained at different control levels and one of them is the regulation of the expression of PKA subunits. We study the expression of PKA subunits during thermal stress. The promoter of each subunit is differentially regulated during this stress. TPK1promoter is the only one upregulated, and accordingly, there is an increase in TPK1 mRNA in response to stress. The BCY1 promoter has low activity, but a high mRNA level is measured. The analysis of mRNA stabilities indicates that the half-life of BCY1 mRNA is greater than that of TPK1, and both are stabilized upon thermal stress. TPKs and BCY1 promoters and 5´UTRs sequences affect the stability of their mRNA. Tpk1 protein levels do not show a significant change during thermal stress but do increase when the cells undergo a second stress, however Bcy1 protein remains constant. Analyzing the in vivo localization of TPK1 mRNA during thermal stress, it was visualized that this mRNA is localized in cytoplasmic granules resistant tocycloheximide. Overall, in response to thermal stress, the mRNAs of the PKA subunits are differentially expressed and more stable; TPK1 mRNA is induced and forms granules and is not translated until the cell leaves the stress conditions