Fig. 5.

Subcellular distribution of matrix metalloproteinase 2 (MMP2) in human muscle fibers. A: human intact (In) and skinned (Sk-F) fibers (segments of 15 fibers in each collected from 1 subject) probed for MMP2 (using Ab92536) and laminin. B: relative amount [arbitrary units (au)] of MMP2 in intact and skinned fibers (7 sets of fibers from 3 subjects, each represented by different-color symbol). Data are individual values and means ± SD. Although the 2 sets of values were not significantly different (P > 0.05, by unpaired Student’s t-test), mean levels are a guide to proportions of total MMP2 associated with the extracellular matrix and intracellular milieu, as in Fig. 3B. C: representative Western blot of human vastus lateralis muscle whole homogenate [Wh, with and without p-aminophenylmercuric acetate (APMA) treatment] and its fractionation into cytosolic (Cyt), membrane (Mem), and cytoskeletal (Csk) compartments, probed for MMP2, SERCA2a, and GAPDH. Most of the MMP2 was cytosolic in the muscle of both human subjects (each muscle sample was examined twice). Stain-Free (blue) gel shows total protein.