Figure 6. CRUs in CS1-null soleus muscle maintain the triadic structure, but the terminal cisternae appear much smaller.

In CS1-null fibres from soleus muscle (C and D), CRUs are mostly in the form of triads, as in WT soleus muscle (A and B), and maintain their normal location and orientation at the edges of the sarcomeric A band. The width of the SR terminal cisternae is, though, visibly smaller than in CS1-null fibres (B and D). Scale bars: A and C, 0.25 μm; B and D, 0.05 μm. TT, T-tubule.