Figure 4. MMPs degrade fibrillin-2 and produce a fibrillin-2 fragment in PDL fibroblast cell layers. The microfibril-containing fraction of the PDL fibroblast cell layer was subjected to fibrillin-2 immunoprecipitation. In control samples at 6 wks, a single 350-kDa protein (fibrillin-2) was detectable (arrowhead). From 6 to 8 wks of culture, a 180-kDa band (asterisk), as well as the 350-kDa band, was detectable. Upon treatment with MMPI, the 180-kDa band decreased in parallel with an increase of the 350-kDa band.