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Identification and characterization of the fifth membrane-type matrix metalloproteinase MT5-MMP
1Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455, USA. peixx003@tc.umn.edu
Abstract:
A new member of the membrane-type matrix metalloproteinase (MT-MMP) subfamily tentatively named MT5-MMP was isolated from mouse brain cDNA library. It is predicted to contain (i) a candidate signal sequence, (ii) a propeptide region with the highly conserved PRCGVPD sequence, (iii) a potential furin recognition motif RRRRNKR, (iv) a zinc-binding catalytic domain, (v) a hemopexin-like domain, (vi) a 24-residue hydrophobic domain as a potential transmembrane domain, and (vii) a short cytosolic domain. Reverse transcriptase-polymerase chain reaction analysis of its transcripts indicates that MT5-MMP is expressed in a brain-specific manner consistent with the origin of its EST clone from cerebellum. It is also highly expressed during embryonic development at stages day 11 and 15. Like other MT-MMPs, MT5-MMP specifically activates progelatinase A when co-expressed in Madin-Darby canine kidney cells. Its ability to activate progelatinase A is dependent on its proteolytic activity since a mutation converting Glu to Ala in the zinc binding motif HE255LGH renders MT5-MMP inactive against progelatinase A. In contrast to other MT-MMPs, MT5-MMP tends to shed from cell surface as soluble proteinases, thus offering flexibility as both a cell bound and soluble proteinase for extracellular matrix remodeling processes. Taken together, these properties serve to distinguish MT5-MMP as a versatile MT-MMP playing an important role in extracellular matrix remodeling events in the brain and during embryonic development.
Insights
A novel membrane-type matrix metalloproteinase, MT5-MMP, was identified in the mouse brain. This enzyme activates progelatinase A and functions as both a cell-bound and soluble proteinase for extracellular matrix remodeling.
Area of Science:
- Biochemistry
- Molecular Biology
- Neuroscience
Background:
- Matrix metalloproteinases (MMPs) are crucial for extracellular matrix (ECM) remodeling.
- Membrane-type MMPs (MT-MMPs) are a subfamily with unique membrane-anchoring domains.
- Understanding novel MT-MMP functions is vital for comprehending ECM dynamics.
Purpose of the Study:
- To identify and characterize a new member of the MT-MMP subfamily.
- To investigate the enzymatic activity and expression patterns of the novel MT5-MMP.
- To elucidate the role of MT5-MMP in ECM remodeling.
Main Methods:
- Isolation of MT5-MMP from a mouse brain cDNA library.
- Reverse transcriptase-polymerase chain reaction (RT-PCR) for transcript analysis.
- Co-expression studies in Madin-Darby canine kidney (MDCK) cells to assess progelatinase A activation.
Main Results:
- MT5-MMP possesses structural features typical of MT-MMPs, including a transmembrane domain.
- Expression is brain-specific and prominent during embryonic development (days 11 and 15).
- MT5-MMP proteolytically activates progelatinase A, dependent on its catalytic activity.
- Unlike other MT-MMPs, MT5-MMP can shed into a soluble form.
Conclusions:
- MT5-MMP is a versatile enzyme involved in ECM remodeling in the brain and during development.
- Its dual cell-bound and soluble nature provides flexibility in regulating ECM processes.
- MT5-MMP represents a distinct member of the MT-MMP family with significant biological implications.