INVESTIGADORES
MORENO Silvia Margarita
congresos y reuniones científicas
Título:
Proteome wide analysis of granular protein complexes evoked by differential heat stress signaling in Saccharomyces cerevisiae
Autor/es:
BARRAZA CARLA; VALACCO MP; FERNANDEZ JORGE GERMAN; MORENO SILVIA; PORTELA PAULA
Lugar:
Buenos Aires
Reunión:
Congreso; Joint meeting of Bioscience Societies; 2017
Institución organizadora:
SAIB y 9 sociedades de biociencias mas
Resumen:
Cellular responses to stress comprise a variety of different mechanisms,including translation arrest and the relocation of translationallyrepressed mRNAs to ribonucleic particles (mRNPs) likestress granules (SGs) and processing bodies (PBs). Given recentevidence on the role of liquid phase transition in signalling and cytosolicmRNPs formation, it is possible that SGs might representregions where certain processes or the activity of enzymes are concentrated.Our results from biochemical approaches and microscopyanalysis show that under mild heat stress the catalytic subunit ofPKA isoform Tpk3 aggregates and promotes aggregation of eIF4G,Pab1 and eIF4E, whereas severe heat stress leads to the formationof PBs and SGs that contain the Tpk2 isoform and a larger 48Stranslation initiation complex. PKA affects the translational responseto heat stress, where each Tpk catalytic isoform appears to havea different role, with Tpk2 and Tpk3 playing negative and positiveroles in the translational response, respectively. We favour a modelwhere depending on the severity of an external stimulus, such asheat stress, each catalytic isoform of PKA interacts with a complexnetwork of distinct protein factors and potential substrates.Our ongoing studies are focused on a global characterization ofprotein complexes under different heat stress conditions. To thisend, we performed a label-free quantitative proteomic analysis ofgranular enriched fraction from mild and severe heat stress using aQExactive. We identified proteins exclusively enriched in mild andsevere heat stress, as well as proteins common to both groups.Gene Onthology analysis showed annotations associated with severalGO biological processes, such as structural constituent of ribosome,RNA binding and translation factor activity. Networks builtfrom these results will let us start defining how different degreesof severity of the same stress evoke a specific response on RNPassembly.