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Human membrane type-2 matrix metalloproteinase is defective in cell-associated activation of progelatinase A
H Miyamori1, T Takino, M Seiki
1Department of Molecular Virology, Cancer Research Institute, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-0934, Japan.
Abstract:
Transfection of the mouse membrane type-2 matrix metalloproteinase (MT2-MMP) gene into COS-1 cells resulted in activation of progelatinase A; however, that of the human gene had no effect. Expression of human and mouse MT2-MMP chimeric proteins revealed the defect of human MT2-MMP which resides in the region between amino acid (aa) residues 155 and 271. Seven aa residues in this region were not conserved between human and mouse MT2-MMP. Substitution with the corresponding mouse residue, proline-183 to serine and glutamine-185 to aspartic acid, recovered cell-associated progelatinase A activation function. These residues are located in the insertion sequence-2 (IS-2), which was conserved in six clones of the human MT2-MMP gene from different sources, except that of proline-183 which was substituted with serine from HT1080 cells. These results indicate that human MT2-MMP is defective in cell-associated activation of progelatinase A, and this is attributed to IS-2. These findings emphasize the importance of IS-2 in MT2-MMP functionality.
Insights
Human membrane type-2 matrix metalloproteinase (MT2-MMP) is defective in activating progelatinase A due to specific amino acid residues in its insertion sequence-2 (IS-2). Mouse MT2-MMP rescues this function, highlighting IS-2
Area of Science:
- Biochemistry and Molecular Biology
- Enzymology
- Cell Biology
Background:
- Matrix metalloproteinases (MMPs) play crucial roles in extracellular matrix remodeling.
- Membrane type-2 matrix metalloproteinase (MT2-MMP) is involved in the activation of progelatinase A.
- Species-specific differences in MT2-MMP function are not fully understood.
Purpose of the Study:
- To investigate the functional differences between mouse and human MT2-MMP in progelatinase A activation.
- To identify the specific region and residues responsible for the defect in human MT2-MMP.
- To elucidate the role of insertion sequence-2 (IS-2) in MT2-MMP functionality.
Main Methods:
- Transfection of mouse and human MT2-MMP genes into COS-1 cells.
- Expression and analysis of human and mouse MT2-MMP chimeric proteins.
- Site-directed mutagenesis to substitute specific amino acid residues.
Main Results:
- Mouse MT2-MMP activated progelatinase A, while human MT2-MMP did not.
- The defect in human MT2-MMP was localized to amino acid residues 155-271.
- Substitution of proline-183 and glutamine-185 in human MT2-MMP with mouse residues restored progelatinase A activation.
Conclusions:
- Human MT2-MMP exhibits a defect in cell-associated progelatinase A activation.
- The insertion sequence-2 (IS-2) region, particularly residues 183 and 185, is critical for MT2-MMP function.
- These findings underscore the importance of IS-2 in MT2-MMP's role in extracellular matrix regulation.