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Regulation of Tration Forces by Stretch-Activated Channels

Munevar et al., J. Cell Sci. 117:85-92 (2004)

Stretch-activated channels allow ion entry upon the application of forces to the membrane and may serve as a primary mechanism for force sensing. It was further proposed that these channels may play a role in detecting the build up of tension in the tail region to trigger retraction. To test these hypotheses, 3T3 fibroblasts were treated with gadolinium, a heavy metal blocker of stretch-activated channels, both globally and in the frontal and tail regions.

Global Inhibition of Stretch-Activated Channels Causes Global Inhibition of Traction Forces

Global treatment with gadolinium causes strong, global inhibition of traction forces before the cell shows noticeable retraction. The right panel shows traction stress, with warm colors representing strong forces. Recording time, 44 min.

Frontal Inhibition of Stretch-Activated Channels Causes Global Inhibition of Traction Forces

Gadolinium solution was released locally to the frontal region, using a release microneedle paired with a suction needle. Frontal inhibition causes strong inhibition of traction forces as does global inhibition, suggesting that stretch-activated channels are operating in the frontal region. Recording time, 29 min.

Tail Inhibition of Stretch-Activated Channels Has no Detectable Effect on Traction Forces

Gadolinium solution was released locally to the tail region, using a release microneedle paired with a suction needle. Tail inhibition causes no detectable effect on traction forces, arguing against the role of stretch-activated channels in detecting tension in the tail region. Recording time, 29 min.