Identification and Characterization of Lutheran Blood Group Glycoprotein as a New Substrate of Membrane-type 1 Matrix Metalloproteinase 1 (MT1-MMP)

Abstract

Membrane-type 1 matrix metalloproteinase 1 (MT1-MMP) is a potent modulator of the pericellular microenvironment and regulates cellular functions in physiological and pathological settings in mammals. MT1-MMP mediates its biological effects through cleavage of specific substrate proteins. However, our knowledge of MT1-MMP substrates remains limited. To identify new substrates of MT1-MMP, we purified proteins associating with MT1-MMP in human epidermoid carcinoma A431 cells and analyzed them by mass spectrometry. We identified 163 proteins, including membrane proteins, cytoplasmic proteins, and functionally unknown proteins. Sixty-four membrane proteins were identified, and they included known MT1-MMP substrates. Of these, eighteen membrane proteins were selected, and we confirmed their association with MT1-MMP using an immunoprecipitation assay. Cells in tissues are surrounded by an extracellular cellular matrix that interacts with cells to regulate their activity (1, 2). Matrix metalloproteinases (MMPs) 3 are endopeptidases responsible for extracellular matrix degradation and thereby regulate turnover of the extracellular matrix. However, recent studies have demonstrated that substrates of MMPs are expanded to a variety of pericellular proteins. MT1-MMP/MMP14 is an integral membrane proteinase that cleaves multiple proteins in the pericellular milieu and thereby regulates various cell functions. Substrates of MT1-MMP identified to date include extracellular matrix proteins (type I collagen, fibronectin, vitronectin, laminin-1 and -5, and others), cell adhesion molecules (CD44, syndecan-1, and ␣v integrin), cytokines (SDF-1 and transforming growth factor-␤ and others), and latent forms of pro-MMPs (pro-MMP-2 and pro-MMP13) (3-5). Processing of these proteins by MT1-MMP alters their activities and thereby regulates a variety of cellular functions, such as motility, invasion, growth, differentiation, and apoptosis. Consistent with these functions, forced expression of MT1-MMP in tumor cells enhances behavior consistent with increased malignancy, such as rapid tumor growth, invasion, and metastasis (6). However, MT1-MMP is normally expressed in various types of cell and mice deficient in MT1-MMP expression (MT1 Ϫ/Ϫ ) display pleiotropic defects (7-10). However, we as yet have only limited knowledge of the physiological substrates of MT1-MMP that could explain such pleiotropic effects.Proteases interact with their substrates at least transiently, but in some cases such interaction is more stable. For instance, type I collagen binds MT1-MMP via a hemopexin-like domain and is cleaved (11, 12). Cleavage of collagen by MT1-MMP regulates cell growth and invasion in a collagen-rich environment (13). CD44, a hyaluronic acid receptor, also binds to the hemopexin of MT1-MMP and is cleaved (14). Expression of CD44 and MT1-MMP in tumor cells promotes cell migration, accompanied by the shedding of CD44 by MT1-MMP (14, 15). pro-MMP-2, which is cleaved by MT1-MMP for activation, forms a tri-molecular complex with MT1-MMP and TIM...

Regulation of invadopodia formation and activity by CD147

“…These results suggest that CD147-MT1-MMP complexes cycle between these two compartments. Other investigators have shown that CD147 associates with both the pro and active forms of MT1-MMP (Egawa et al, 2006;Niiya et al, 2009). In addition, we found that upregulation of CD147 in non-transformed MCF-10A epithelial cells results in enrichment of both CD147 and MT1-MMP in membrane compartments with characteristics similar to lipid raft domains, supporting previous observations that invadopodia formation and activity are dependent on these domains (Yamaguchi et al, 2009).…”

Cleavage of hepatocyte growth factor activator inhibitor‐1 by membrane‐type MMP‐1 activates matriptase

“…This led us to examine the physiological significance of HAI-1 shedding by MT1-MMP. While we were studying the cleavage of HAI-1 by MT1-MMP, Niiya et al (30) identified HAI-1 as one of many MT1-MMP-associated proteins by proteomics screening.…”

When MT1-MMP meets ADAMs

“…In addition to ADAM9, MT1-MMP can physically interact with other ADAM family members, including ADAM10 and ADAM15, 24 suggesting that there is a functional relationship between MT1-MMP and other ADAMs. We examined whether the expression of ADAMs10/15 is altered by the loss of MT1-MMP.…”