Figure 4
Differential p70S6K stretch response in isolated C57 and γ-SG-/-muscles. EDL muscles from C57 and γ-SG-/- mice were maintained in oxygenated high glucose DMEM and subjected to passive stretching for 30 or 90 min. (A) Immunoblot of γ-SG following immunoprecipitation with anti-P-Tyr or lysate only, showing γ-SG phosphorylation in response to 30 min of stretch. (B) Representative immunoblots of P-p70S6K (T389 and T421/S424 sites) and tubulin. (C, D) Quantification of P-p70S6K T389 (C) and T421/S424 (D), normalized to tubulin. Samples for each time point were run on separate immunoblots and normalized to C57 NS. n = 3-5 muscles per genotype, condition, and time point. Bars represent mean ± standard error. All datasets were tested by two-way ANOVA. Stretch was statistically significant for T421/S424 after 30 min of stretch; genotype, stretch, and the interaction between them were statistically significant T389 after 90 min of stretch, by two-way ANOVA. *Significantly different from C57 S at 90 min by two-way ANOVA with Tukey’s multiple comparisons test. NS, non-stretched; S, stretched.