Lectures in University of Brawijaya, 2013
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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

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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

Lectures in University of Brawijaya, 2013

Biological Responses to Environmental Stress

Tetsuro Ishii, PhD.

Professor Emeritus, University of Tsukuba, Japan


Lectures in university of brawijaya 2013 biological responses to environmental stress

Animals have developed defense system against environmental stress agents

Plant

Animal

poisons

Detoxification system

Natural immunity

Repair system

Apoptosis

Toxic agents

UV, As, Heavy metals

Infection

Bacteria, Virus


Lectures in university of brawijaya 2013 biological responses to environmental stress

Stress causes upregulation of stress proteins

Detection by sensors

stressor

Cell damages

Activation of transcription factors

Heat shock

Oxidative stress

HSFs

Nrf2

Acquire tolerance

Gene activation

Protein synthesis

Repair damages


Lectures in university of brawijaya 2013 biological responses to environmental stress

Biological Responses to Environmental Stress

1. Cellular response to heat

2. Cellular response to electrophiles and reactive oxygen species

3. Nrf2 target genes


Lectures in university of brawijaya 2013 biological responses to environmental stress

Heat was necessary to create life

Hydrothermal vent

Yellowstone hot spring

Adaptation to heat is most important for life.


Lectures in university of brawijaya 2013 biological responses to environmental stress

Heat shock induces various proteins in cells

Temperature shift

43°C

37°C

Activation of heat shock factors

Induction of heat shock proteins (HSPs)

Has60, Hsp70, Hsp90, etc.


Lectures in university of brawijaya 2013 biological responses to environmental stress

Heat shock protein (HSP) family

HSP110

HSP100

HSP90

HSP70 (DNAK)

HSP60 (chaperonin, GroEL)

HSP47

HSP40 (DNAJ)

HSP33

HSP27

HSP15

HSP10

Some of these proteins are constitutively expressed and play their roles under normal temperature.


Lectures in university of brawijaya 2013 biological responses to environmental stress

Some proteins return to native form following heat denaturation

denature or unfolding

Renature or refolding

But, many proteins became aggregated when denatured


Lectures in university of brawijaya 2013 biological responses to environmental stress

Denatured/unfolded proteins tend to aggregate

Protein aggregates


Lectures in university of brawijaya 2013 biological responses to environmental stress

Inhibition of protein aggregation by Dank-ClpB

Heat shock

Aggregation

Native form


Lectures in university of brawijaya 2013 biological responses to environmental stress

Chaperonin inhibits protein aggregation

albumin

Native form

Urea + DTT

Denatured form

Enzyme activity

turbidity

± chaperonin


Lectures in university of brawijaya 2013 biological responses to environmental stress

ATP-dependent folding of GFP-protein by chaperonin

GFP fluorescence

Time (min)

(-) chaperonin

Inhibition of protein aggregate by chaperonin

Opitical Scattering

(+) chaperonin

Time (min)


Lectures in university of brawijaya 2013 biological responses to environmental stress

Chaperonin inhibits protein aggregate by heat treatment

Without chaperonin

With chaperonin


Lectures in university of brawijaya 2013 biological responses to environmental stress

Double ring structure of chaperonin, GroEL


Lectures in university of brawijaya 2013 biological responses to environmental stress

GroEL-GroES complex provides space for protein folding


Lectures in university of brawijaya 2013 biological responses to environmental stress

Discovery of chaperonin

“Molecular chaperon” was found in different systems


Lectures in university of brawijaya 2013 biological responses to environmental stress

Functions of chaperonin during protein synthesis

Protein synthesis

hsp

Miss-folding

chaperonin

aggregates

normal folding


Lectures in university of brawijaya 2013 biological responses to environmental stress

Role of chaperons in protein synthesis


Lectures in university of brawijaya 2013 biological responses to environmental stress

Role of chaperons in protein targeting to mitochondria


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