CH391L/S13/Mechanosensing

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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, 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.
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The first pressure-responsive gene was found in 1989 <cite>OmpH_discovery</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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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].
==Mechanosensitive Promoters==
==Mechanosensitive Promoters==

Revision as of 19:02, 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, 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.

The first pressure-responsive gene was found in 1989 [1] 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. Bartlett D, Wright M, Yayanos AA, and Silverman M. . pmid:2479840. PubMed HubMed [OmpHdiscovery]
    First discovery of pressure-regulated gene

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