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