CHARACTERIZATION OF THE UNFOLDED PROTEIN RESPONSE THROUGH THE USE OF FLUORESCENT REPORTERS IN CULTURED SINGLE CELLS AND IN DISEASE MODELS

MARÍA COTARELO; MARIELA VEGGETTI; ALEJANDRO COLMAN-LERNER; LIONEL MÜLLER IGAZ; MATÍAS BLAUSTEIN

Buenos Aires

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

The Unfolded Protein Response (UPR) is a cellular stress signalingcascade essentially triggered by the accumulation of misfoldedproteins in the Endoplasmic Reticulum (ER). Three mechanisticallydistinct pathways (IRE1, PERK and ATF6) make up this collectiveresponse aimed at restoring homeostasis. However, if this objectiveis not met within a logical time span, the UPR triggers apoptosis.This dichotomy of outcomes makes determining the cell?s fate a realenigma which could be solved through a clear characterization ofthe UPR dynamics.In order to do this, we employed a set of fluorescent reporters thatallows us to monitor the activation of the UPR in human single cellsand in real time. We have previously characterized novel reportersfor the ATF6 and IRE1 pathways, and we describe here the designof new reporters for the PERK pathway. We have also developed aprotocol for automated imaging and segmentation of cells as well asfor quantitative analysis of UPR activation. We aim to study the activationdynamics of the three UPR pathways in single cells in orderto shed light onto the decision-making mechanisms involved in celldeath and survival.Interestingly, some evidences show that the UPR might be associatedwith neurodegenerative diseases: activation of UPR in patientssuffering from frontotemporal lobar degeneration (FTLD) and amyotrophiclateral sclerosis (ALS) has been linked to the toxicity of TarDNA binding Protein-43 (TDP-43), the main component of intracellularinclusions related to these diseases. Confirmation of this integratednetwork would open the possibility of designing new therapiestargeted to patients suffering from neurodegeneration.