INVESTIGADORES
MORENO Silvia Margarita
congresos y reuniones científicas
Título:
Structure of the dimerization domain of Bcy1, the regulatory subunit of the cAMP dependent protein kinase from Saccharomyces cerevisiae, and interaction with a peptide derived from IRA2, a GTPase activating protein involved in the cAMP signalling pathway.
Autor/es:
GONZALEZ BARDECI NICOLAS; CARAMELO JULIO; ROSSI SILVIA; LARRIEUX NICOLE; TRATJENBERG FELIPE; BUSCHIAZZO ALEJANDRO; MORENO SILVIA
Lugar:
Puerto Varas
Reunión:
Congreso; XII ¨PABMB congress; 2013
Institución organizadora:
SAIB, PABMB, Soc bioq y biol Mol chile
Resumen:
A prototypic member of the Ser/Thr kinase family is the cAMP dependent protein kinase (PKA). In most organisms it exists as an inactive holoenzyme, consistent of two catalytic (C) subunits and a regulatory (R) subunit dimer. When extracellular signals trigger cAMP synthesis, two molecules of the second messenger bind each R subunit, realeasing fully active C subunits. In mammals, PKA holoenzyme is confined to specific subcellular compartments by high affinity interaction between the dimerization and docking (D/D) domain of R2  and an amphipatic a ? helix of scaffold proteins belonging to A Kinase Anchoring Proteins (AKAPs) family In yeast, PKA is involved in the regulation of processes related to nutrient source and availability, response to stress, etc. No yeast AKAPs have been described to date. We have already reported, the interaction of Bcy1 with a 20 aminoacid peptide of IRA2 and have obtained a low resolution structure of the D/D of Bcy1. Here we present a spectroscopic and crystallographic study addressed to gain insight into this interaction. The IRA2 peptide folds into an amphipatic a ? helix, and interacts with Bcy1 with nM affinity. Crystallization trials on Bcy1 D/D domain were succesfully performed; crystals diffracted at 2.5 A resolution, and belong to the P21 space group. Four dimers were found in the asymmetric unit. The first approaches to solve the structure by molecular replacement methods showed structural differences with the D/D domains of mammals.