Fig. 6. Potential roles of MMP2 in mediating Müllerian duct regression. Activation of the MIS signaling cascade induces expression of MMP2 in the Müllerian duct mesenchyme. Latent or pro-MMP2 is secreted into the extracellular space, where it is activated to its mature form by membrane bound metalloproteinases such as MMMP14. Cell death of the Müllerian duct epithelium may occur by MMP2 cleavage of a factor secreted by the mesenchyme. MMP2 activity may result in the degradation of a survival factor or activation of a death factor. Alternatively, MMP2 could cause apoptosis by cleaving substrates on the epithelial cell, such as the epithelial cell basement membrane.