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. Author manuscript; available in PMC: 2009 Dec 1.
Published in final edited form as: Cell Motil Cytoskeleton. 2008 Dec;65(12):964–978. doi: 10.1002/cm.20319

Figure 8.

Figure 8

Membrane stretch experiments demonstrate the altered expression and response of plakoglobin, N-cadherin and Cx43 to mechanical stimuli. (A,B) Confocal microscopy images of wildtype (wt) cells under control conditions (A) or after 4 hr of pulstile stretch (B) immunostained to show the amount of junctional N-cadherin expression. Increased levels of N-cadherin at cell borders can be seen in response to stretch. Scale bars = 20 μm. The number of pixels occupied by bright immunoreactive signal was quantified and expressed as a proportion of total pixels occupied by cells to measure the amount of signal for each protein at cell-cell junctions. These measurements are shown in the bar graphs depicted in this figure. (C) The amount of plakoglobin was similar in wt and insS cells at baseline. Stretch-induced up-regulation of plakoglobin was suppressed in insS cells compared to wt cells. Naxos cells could not be analyzed because of the limited amount of junctional plakoglobin. (D,F) Expression of N-cadherin followed a similar pattern as for plakoglobin. While cells expressing wildtype (wt) or mutant plakoglobin had similar N-cadherin expression levels at baseline, up-regulation in response to 1 and 4 hr of stretch was diminished for in cells expressing mutant plakoglobin. (E,G) Expression of connexin43 (Cx43) was diminished under basal (non-stretched) conditions in cells expressing mutant plakoglobin. Stretch-induced up-regulation of Cx43 was also appeared to be diminished compared to wt cells. However, due to the lower baseline, the lower stretch response cannot be attributed exclusively to decreased upregulation. (F, G) Naxos cells exhibited a similar pattern for N-cadherin and Cx43 expression, exhibiting lower expression at one and four hours of stretch, and with decreased expression at baseline for Cx43 only. For each condition in each experiment, n=5. For insS: plakoglobin, p<0.05 at one hour, p< 0.0001 at four hours; for both mutants: for N-cadherin, p<0.01 at one hour and four hours; for Cx43, p<0.05 at baseline, p<0.0001 at one and four hours, each versus wt at the same times.