Details

Autor(en) / Beteiligte

• Lehti, Kaisa
• Lohi, Jouko
• Juntunen, Minna M.
• Pei, Duanqing
• Keski-Oja, Jorma

Titel

Oligomerization through Hemopexin and Cytoplasmic Domains Regulates the Activity and Turnover of Membrane-type 1 Matrix Metalloproteinase

Ist Teil von

• The Journal of biological chemistry, 2002-03, Vol.277 (10), p.8440-8448

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2002

Quelle

MEDLINE

Beschreibungen/Notizen

• The formation of multimeric complexes by membrane-type 1 matrix metalloproteinase (MT1-MMP) may facilitate its autocatalytic inactivation or proMMP-2 activation on the cell surface. To characterize these processes, we expressed various glutathione S-transferase/MT1-MMP fusion proteins in human HT-1080 fibrosarcoma cells and SV40-transformed lung fibroblasts and analyzed their effects on MT1-MMP activity and potential homophilic interactions. We report here that MT1-MMP is expressed on the cell surface as oligomeric 200–240-kDa complexes containing both the active 60-kDa and autocatalytically processed 43-kDa species. Overexpression of a glutathione S-transferase/MT1-MMP fusion protein containing the transmembrane and cytoplasmic domains of MT1-MMP inhibited the phorbol 12-myristate 13-acetate-induced autocatalytic cleavage of endogenous MT1-MMP to the 43-kDa species, but not proMMP-2 activation. On the other hand, a similar fusion protein with the hemopexin, transmembrane, and cytoplasmic domains inhibited proMMP-2 activation in a dominant-negative fashion. These results suggest that both the autocatalytic cleavage of MT1-MMP and proMMP-2 activation may be regulated by oligomerization through the cytoplasmic and hemopexin domains. Indeed, either domain, when attached to the cell membrane by a transmembrane domain, formed stable homophilic complexes. Copurification of MT1-MMP with these fusion proteins correlated with their cell-surface co-localization. Thus, MT1-MMP oligomerization through the hemopexin, transmembrane, and cytoplasmic domains controls its catalytic activity.