AI Article Synopsis
- The localization of matrix metalloproteinases (MMPs) on the cell surface is crucial for both processing cell surface proteins and degrading the extracellular matrix (ECM).
- This study highlights that cholesterol sulfate (CS) enhances MMP-7's ability to degrade certain proteins like laminin-332, while inhibiting degradation of others, indicating that CS can change MMP-7's substrate preferences.
- The findings suggest that CS facilitates MMP-7’s linkage to its substrates, promoting proteolytic activity which could contribute to cancer cell migration and metastasis by detaching cells from their surrounding ECM.
Article Abstract
Localization of secreted matrix metalloproteinases (MMPs) on the cell surface is required not only for processing of cell surface proteins, but also for controlled degradation of the extracellular matrix (ECM). Our previous study demonstrated that binding of MMP-7 (matrilysin) to cell surface cholesterol sulfate (CS) is essential for the cell membrane-associated proteolytic action of this MMP. In this study, we investigated the role of CS in the MMP-7-catalyzed degradation of protein components of ECM. We found that the degradation of laminin-332 (laminin-5) catalyzed by MMP-7 was accelerated dramatically in the presence of CS, whereas the sulfated lipid inhibited the degradation of casein catalyzed by the protease. The MMP-7-catalyzed degradation of fibronectin was partially inhibited in the presence of low concentrations of CS, whereas it was accelerated significantly at high concentrations of the lipid. Therefore, it is likely that CS alters the substrate preference of MMP-7. We also found that the proteins of which MMP-7-catalyzed degradation were accelerated by CS also had affinities for CS, suggesting that CS facilitates the proteolyses by cross-linking MMP-7 to its substrates. Moreover, MMP-7 tethered to cancer cell surface via CS degraded fibronectin and laminin-332 coated on a culture plate. The degradations of the adhesive proteins led to significant detachment of the cells from the plate. Taken together, our findings provide a novel mechanism in which cell surface CS promotes the proteolytic activities of MMP-7 toward selective substrates in the pericellular ECM, thereby contributing to cancer cell migration and metastasis.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2937913 | PMC |
| http://dx.doi.org/10.1074/jbc.M110.136994 | DOI Listing |
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