Fig. 2
Proteomic profiling of slow and fast soleus muscle fibers reveals novel fiber type-specific marker proteins. a ProFiT analysis of isolated single fibers from the soleus (n = 4). Each bar represents the relative abundance of MYH isoforms in one fiber in relation to the total sum of intensities for MYH1, MYH2, MYH4, and MYH7. Immunostaining with MYH7 (slow type I, blue) and MYH2 (fast type IIa, green) antibodies. b Volcano plot comparing protein fold-changes (log2-scale) in soleus type I and type IIa fibers. Colored circles represent differentially regulated proteins (difference > 1.5-fold, p value < 0.05). c 1D annotation enrichment showing specific gene ontology terms enriched in soleus type I and type IIa fibers. d Co-immunostainings of carbamoyl-phosphate synthetase 1(CPS1) and myosin-7 (MYH7) on soleus cryosections (scale bar = 50 μm). e Quantitative analysis of the CPS1 fluorescent signal in type I (MYH7) positive and negative myofibers using violin plots. Significances were calculated by two-sided t tests (n = 42). f Graphical visualization of the urea cycle. Proteins involved in this pathway that were significantly enriched in soleus type I fibers are highlighted in blue