Levels of MTMR4 and FGFR-1 are not maintained in the denervated gastrocnemius of <i>Nedd4-1</i> SMS-KO mice, while cleaved Notch-1 expression is increased.

<p>(A) Representative Western blots of MTMR4, FGFR1, cleaved Notch-1 (Notch-1 ICD) and HPRT (as a loading control) in protein lysates from denervated gastrocnemius muscle (Den) or the contralateral control gastrocnemius (Con) muscle in <i>Nedd4-1</i> SMS-KO and littermate <i>Myo^Cre;Nedd4-1^+/+</i> control mice at 1 and 2 weeks post tibial nerve transection. (B) The chemiluminescent signal was quantified, MTMR4, FGFR1 and Notch-1 protein levels were normalized to the corresponding HPRT levels (lane matched) and numerical values are depicted in bar graphs. For each of MTMR4, FGFR1 and Notch-1, protein levels in denervated (Exp) muscle are expressed as a fraction of the protein level in control (Con) muscle. MTMR4 levels were significantly decreased in denervated compared to control gastrocnemius muscle in both <i>Nedd4-1</i> SMS-KO (n = 6) and <i>Myo^Cre;Nedd4-1^+/+</i> mice (n = 6) mice at 2 weeks (p<0.05), but there was no difference in the magnitude of MTMR4 decrease between the <i>Nedd4-1</i> SMS-KO compared to control mice. FGFR1 levels were similarly significantly decreased in denervated compared to control gastrocnemius muscle in both <i>Nedd4-1</i> SMS-KO (n = 8) and littermate <i>Myo^Cre;Nedd4-1^+/+</i> control mice (n = 8) mice at 1 week and 2 weeks (p<0.05) post tibial nerve transection, and again there was no difference in the magnitude of the decrease between the 2 cohorts of mice at either timepoint. Cleaved Notch-1 levels (Notch ICD) were significantly increased in denervated compared to control gastrocnemius in both <i>Nedd4-1</i> SMS-KO (n = 6) and <i>Myo^Cre;Nedd4-1^+/+</i> control mice (n = 6) mice at 2 weeks (p<0.05), but not at 1 week. There was no difference in the magnitude of the increase between the 2 cohorts of mice. Data are mean ± SEM.