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. 2012 Apr 3;7(4):e34177. doi: 10.1371/journal.pone.0034177

Figure 4. Selective cellular trafficking of 68.

Figure 4

kDa and 65 kDa MMP-2 isoforms in model H9C2 cells. I. Relative distributions of 68 (FL) and 65 kDa MMP-2 (NTT) isoforms in cytosolic and mitochondrial fractions following transient transfection with the respective expression plasmids. The quality of the cytosolic and mitochondrial fractions was assessed by Western blots for KDEL (endoplasmic reticulum), CIV (Complex IV, mitochondrial matrix) and LDH (lactate dehydrogenase, cytosol). A faint band of the 68 kDa MMP-2 isoform is present in the cytosolic fraction of cells transfected with 68 kDa MMP2 cDNA, but not in the mitochondria-enriched fraction. The 65 kDa MMP-2 isoform is present in both the cytosolic and mitochondrial fractions of cells transfected with the NTT-MMP-2 cDNA with a ratio of approximately 3∶1. The mitochondrial fractions did include faintly detectable KDEL bands, consistent with the presence of the mitochondria-associated endoplasmic reticulum in the preparation. II. H9C2 cells were transiently transfected with an empty pcDNA3.1 expression plasmid (-) or expression plasmids encoding either the 68 kDa (Full Length) or N-Terminal Truncated 65 kDa MMP-2. Western blot of the extracellular (conditioned medium) fraction revealed the 68 kDa FL, secreted isoform of MMP-2, while the NTT isoform was not detected. The FL 68 kDa isoform was not detected in mitochondria-enriched fractions, while the 65 kDa NTT isoform was present in this fraction.