Fig. 3.

Amounts of matrix metalloproteinase 2 (MMP2) in intact and skinned rat muscle fibers. A: Western blot of MMP2, probed with Ab92536, and antibodies against the extracellular matrix protein laminin, and SERCA2a in segments of intact (In) and skinned (Sk-F) soleus (SOL) fibers (15 fiber segments in each). SERCA2a, along with myosin on the Stain-Free (blue) gel, reflects loading amounts of total protein. Soleus homogenate (homo) with or without p-aminophenylmercuric acetate (APMA) treatment and M/R pro-MMP2 pure protein were loaded on the same gel. Pro- and active MMP2, nonspecific bands, and molecular weight markers (M) are indicated. B: relative amount [arbitrary units (au)] of MMP2 in intact and skinned fibers. Values are pooled data and means ± SD; n = 8 sets of fiber segments in each. *P < 0.05 (by unpaired Student’s t-test). Labels on right denote MMP2 that can be apportioned to extracellular matrix and intracellular milieu, using the mean values.