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Lectures in University of Brawijaya, 2013 Biological Responses to Environmental Stress Tetsuro Ishii, PhD. Professor Emeritus, University of Tsukuba, Japan. Animals have developed defense system against environmental stress agents. Plant. Animal. poisons. Detoxification system - PowerPoint PPT Presentation
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Lectures in University of Brawijaya, 2013
Biological Responses to Environmental Stress
Tetsuro Ishii, PhD.Professor Emeritus, University of Tsukuba, Japan
AnimalPlantpoisonsDetoxification systemNatural immunityRepair systemApoptosisAnimals have developed defense system against environmental stress agentsToxic agentsUV, As, Heavy metalsInfectionBacteria, Virus
Stress causes upregulation of stress proteinsstressorDetection by sensorsGene activationProtein synthesisRepair damagesCell damagesAcquire toleranceActivation of transcription factors
Biological Responses to Environmental Stress
1. Cellular response to heat 2. Cellular response to electrophiles and reactive oxygen species 3. Nrf2 target genes
Heat was necessary to create lifeAdaptation to heat is most important for life.Yellowstone hot springHydrothermal vent
Heat shock induces various proteins in cells37C43CTemperature shiftInduction of heat shock proteins (HSPs)Has60, Hsp70, Hsp90, etc.Activation of heat shock factors
Heat shock protein (HSP) familyHSP110HSP100HSP90HSP70 (DNAK)HSP60 (chaperonin, GroEL)HSP47HSP40 (DNAJ)HSP33HSP27HSP15HSP10Some of these proteins are constitutively expressed and play their roles under normal temperature.
Some proteins return to native form following heat denaturationdenature or unfoldingRenature or refoldingBut, many proteins became aggregated when denatured
Denatured/unfolded proteins tend to aggregateProtein aggregates
Inhibition of protein aggregation by Dank-ClpBHeat shockAggregationNative form
Chaperonin inhibits protein aggregationNative formDenatured formUrea + DTT chaperoninalbuminEnzyme activityturbidity
Opitical ScatteringInhibition of protein aggregate by chaperoninATP-dependent folding of GFP-protein by chaperoninGFP fluorescence(+) chaperonin(-) chaperoninTime (min)Time (min)
Without chaperoninWith chaperoninChaperonin inhibits protein aggregate by heat treatment
Double ring structure of chaperonin, GroEL
GroEL-GroES complex provides space for protein folding
Discovery of chaperoninMolecular chaperon was found in different systems
Functions of chaperonin during protein synthesischaperoninhspnormal foldingaggregatesProtein synthesisMiss-folding
Role of chaperons in protein synthesis
Role of chaperons in protein targeting to mitochondria
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