INVESTIGADORES
MORENO Silvia Margarita
congresos y reuniones científicas
Título:
PDK1 HOMOLOGUE DELETION IMPAIRS THE REGULATION OF PKA IN SACCHAROMYCES CEREVISIAE
Autor/es:
TUDISCA,V.; MORENO, S.; PORTELA, P.
Lugar:
Mar del Plata, Buenos Aires
Reunión:
Congreso; 43 Reunion Anual SAIB; 2007
Institución organizadora:
SAIB
Resumen:
In mammalian cells, the PDK1 protein kinase controls numerous processes through substrate phosphorylation on a Thr in a conserved motif. The yeast S.cerevisiae contains three PDK1 homologues: Pkh1, Pkh2 and Pkh3. Yeast cells lacking both Pkh1 and Pkh2 are nonviable and a temperature-sensitive mutant, pkh1D398Gpkh2 delta showed defects in actin organization, endocytosis and trehalose levels. Whereas in mammalian and yeast cells Pdk1/Pkh substrates have been identified, the phosphorylation of the conserved Thr in the catalytic loop of PKA still remains enigmatic, particularly the role of this phosphorylation on in vivo regulation of PKA activity. S.cerevisiae PKA encodes three catalytic subunits: Tpk1, Tpk2 and Tpk3. Here we show that Pkh1 is capable of phosphorylating Tpk1 in vivo increasing the interaction with the regulatory subunit Bcy1. Tpk1 and an inactive version tpk1dead were phosphorylated by Pkh1 and Pkh2. Using pkhD398Gpkh2 delta mutant we could study the effect of inactivation of Pkh activity over several phenotypes controlled by Tpk1, namely, a mislocalization of Tpk1-GFP under fermentative growth, a reduction in glucose induced decrease of trehalose and glycogen levels, and an increase on the PKA dependent phosphorylation state of Msn2 transcription factor. These results point to the Pkh kinase as upstream regulator of the cAMP dependent response of PKA in S. cerevisiae.