The SR in skeletal muscles of CD97Ko mice is morphologically abnormal.

<p><b>A</b> Representative electron micrographs of longitudinal ultrathin sections of WT and CD97Ko mice. Note the altered morphology of the SR which was frequently swollen (arrow heads), whereas myofibrils and mitochondria retained normal structures in CD97Ko mice. <b>B-E</b> Quantitative measurements of several morphometric parameters based on electron micrographs of the quadriceps muscle (n = 4 mice/strain, 25 micrographs/animal, mean ± SEM; *p<0.05, **p<0.01, *** p<0.001, t-test). D shows the number of AI-junctions and triads/100 µm² area occupied by myofibrils.