Difference between revisions of "CH391L/S13/Mechanosensing"

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#OmpH discovery pmid=2479840
#OmpHdiscovery pmid=2479840
//First discovery of pressure-regulated gene
//First discovery of pressure-regulated gene

Revision as of 15:01, 8 April 2013


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 [ref to bartlett 1989] 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


  1. Bartlett D, Wright M, Yayanos AA, and Silverman M. Isolation of a gene regulated by hydrostatic pressure in a deep-sea bacterium. Nature. 1989 Nov 30;342(6249):572-4. DOI:10.1038/342572a0 | PubMed ID:2479840 | HubMed [OmpHdiscovery]
    First discovery of pressure-regulated gene