FIG. 4.

A CRM1 inhibitor blocks agonist-induced increases in cardiomyocyte size and sarcomere organization. (A) NRVMs were treated with PE (20 μM) or FBS (5%) for 48 h in the absence or presence of LMB (18.5 nM). Total cellular protein was quantified by the Bradford assay and is presented as a percentage of that in untreated cells. Values are averages from eight independent samples ± standard deviations. (B) NRVMs were treated as described for panel A and trypsinized for Coulter Counter analysis. Average cell volumes (in cubic micrometers) were determined for 10⁴ cells. Error bars represent standard deviations of results from three independent experiments. (C) NRVMs were treated for 48 h with PE (20 μM) or FBS (5%) in the absence or presence of LMB (18.5 nM). Cells were fixed and stained for α-actinin to reveal sarcomeres by indirect immunofluorescence. LMB prevents the enhanced organization of the sarcomeres in response to hypertrophic agonists.