Identification of MMP Substrates in the Mammary Gland
Abstract
Targeted expression of autoactivated rat Stromelysin-l in mouse mammary glands was shown to induce hyperplasias and breast cancer, demonstrating that this matrix metalloprotease can act as a natural tumor promoter (Sternlicht et al., 1999). To understand how MMP-3 can influence cancer susceptibility, the yeast two-hybrid system was used to identify interacting proteins as potential novel substrates. The hemopexin domain of MMP-3 interacted with the C-termini of Wnt5a and b in a two-hybrid assay. This interaction is quite specific, since MMP-3 did not interact with the C-termini of Wnt2, 4, 6, 7b or 10b. Furthermore, the hemopexin domains of MMP-2 and MMP-14 did not interact with any of the Wnts tested here. Recombinant MMP-3 catalytic domain can cleave both soluble Wnt5b as well as cell bound Wnt5a and b immunoprecipitated from RIPA cell lysates. Both Wnts were cleaved within the minimal MMP-3 binding domain, consistent with the observed Wnt/catalytic domain two-hybrid interactions. Cleavage of soluble Wnt5a was not observed and may require the presence of a hemopexin domain on MMP-3. These observations suggest that both Wnt5a and b are MMP-3 substrates, but only Wnt5b is co-expressed with MMP-3 in the ductal microenvironment during mammary gland development.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2004
- Accession Number
- ADA430554
Entities
People
- Gerrit J. Dijkgraaf
- Zena Werb
Organizations
- University of California, San Francisco