CH391L/S13/Mechanosensing

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(Introduction)
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*Direct force, as in the case of body weight on a bone
*Direct force, as in the case of body weight on a bone
*Osmotic pressure, resulting from a difference in solute concentrations across a semi-permeable membrane
*Osmotic pressure, resulting from a difference in solute concentrations across a semi-permeable membrane
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High hydrostatic pressure (HHP) can cause dissociation of multimeric proteins, decreased membrane fluidity, and even unfolding of monomeric proteins in extreme cases [biotech review]. In some cases, changes in mechanical stress result in differential gene expression driven by mechanosensitive promoters or repressors. Genes that have increased expression might include cold- and heat-shock and other stress response proteins, barostable synthases [vezzi ref?], or membrane proteins [add reference]. Down-regulated genes might include nutrient transporters [Mal operan ref]. In other cases, porin proteins which provide ion diffusion pathways are opened in response to osmotic stress across the membrane.
+
High hydrostatic pressure (HHP) can cause dissociation of multimeric proteins, shifts in reaction equilibria, decreased membrane fluidity, and even unfolding of monomeric proteins in extreme cases (reviewed in <cite>biotechreview</cite>. In some cases, changes in mechanical stress result in differential gene expression driven by mechanosensitive promoters or repressors. Genes that have increased expression might include cold- and heat-shock and other stress response proteins, barostable synthases [vezzi ref?], or membrane proteins [add reference]. Down-regulated genes might include nutrient transporters [Mal operan ref]. In other cases, porin proteins which provide ion diffusion pathways are opened in response to osmotic stress across the membrane.
The first pressure-responsive gene was found in 1989 <cite>OmpHdiscovery</cite> in a deep-ocean bacterium, ''Photobacterium profundum'' strain SS9. The gene encodes for OmpH, a large transmembrane protein which is involved in nutrient uptake. Later work found that the operon also contained two outer membrane proteins, OmpL [include ref] (induced at lower pressures ~1atm) and OmpI [include ref] (induced at much higher pressures ~400atm). These pressure inducible genes were found to be essential for survival under HHP growth conditions[include a ref].
The first pressure-responsive gene was found in 1989 <cite>OmpHdiscovery</cite> in a deep-ocean bacterium, ''Photobacterium profundum'' strain SS9. The gene encodes for OmpH, a large transmembrane protein which is involved in nutrient uptake. Later work found that the operon also contained two outer membrane proteins, OmpL [include ref] (induced at lower pressures ~1atm) and OmpI [include ref] (induced at much higher pressures ~400atm). These pressure inducible genes were found to be essential for survival under HHP growth conditions[include a ref].
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#OmpHdiscovery pmid=2479840
#OmpHdiscovery pmid=2479840
//First discovery of pressure-regulated gene
//First discovery of pressure-regulated gene
 +
#biotechreview pmid=20198911
</biblio>
</biblio>

Revision as of 18:06, 8 April 2013

Contents

Introduction

Mechanosensing refers to the ability of an organism to respond to changes in mechanical force on them or their environment. The mechanical stress can be in a variety of forms:

  • Hydrostatic pressure, as in the case of deep ocean environments
  • Fluid shear stress, as in the case of blood flowing through veins
  • Direct force, as in the case of body weight on a bone
  • Osmotic pressure, resulting from a difference in solute concentrations across a semi-permeable membrane

High hydrostatic pressure (HHP) can cause dissociation of multimeric proteins, shifts in reaction equilibria, decreased membrane fluidity, and even unfolding of monomeric proteins in extreme cases (reviewed in [1]. In some cases, changes in mechanical stress result in differential gene expression driven by mechanosensitive promoters or repressors. Genes that have increased expression might include cold- and heat-shock and other stress response proteins, barostable synthases [vezzi ref?], or membrane proteins [add reference]. Down-regulated genes might include nutrient transporters [Mal operan ref]. In other cases, porin proteins which provide ion diffusion pathways are opened in response to osmotic stress across the membrane.

The first pressure-responsive gene was found in 1989 [2] in a deep-ocean bacterium, Photobacterium profundum strain SS9. The gene encodes for OmpH, a large transmembrane protein which is involved in nutrient uptake. Later work found that the operon also contained two outer membrane proteins, OmpL [include ref] (induced at lower pressures ~1atm) and OmpI [include ref] (induced at much higher pressures ~400atm). These pressure inducible genes were found to be essential for survival under HHP growth conditions[include a ref].

Mechanosensitive Promoters

Mechanosensitive Channels

iGEM Connection

Future Directions

References

  1. Morozkina EV, Slutskaia ES, Fedorova TV, Tugaĭ TI, Golubeva LI, and Koroleva OV. . pmid:20198911. PubMed HubMed [biotechreview]
  2. Bartlett D, Wright M, Yayanos AA, and Silverman M. . pmid:2479840. PubMed HubMed [OmpHdiscovery]
    First discovery of pressure-regulated gene

All Medline abstracts: PubMed HubMed
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