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Updated: Jan 27, 2026
Detection of Functional Matrix Metalloproteinases by Zymography
Published on: November 8, 2010
Matrix Metalloproteinases -14, -9 and -2 are Localized to the Podosome and Involved in Podosome Development in the
S E Thatcher1, J E Black2, H Tanaka3
1Department of Pharmacology and Nutritional Sciences, University of Kentucky, USA.
Aim:
The purpose of the study was to localize matrix metalloproteinase (MMP)-14, -9, and -2 in the A7r5 smooth muscle cell and to understand the interaction between these MMPs and the cytoskeleton. This interaction was observed under non-stimulating and phorbol 12, 13-dibutyrate (PDBu)-stimulating conditions.
Methods:
Confocal microscopy was utilized to define the localizations of MMPs and tissue inhibitor of matrix metalloproteinases (TIMPs) in the A7r5 cell and to determine interaction between MMPs and the cytoskeleton. Under PDBu-stimulating conditions, the presence of MMP active forms and activity by gel zymography was evaluated in the A7r5 cell. Actin and microtubule-polymerization inhibitors were used to evaluate MMP interaction with the cytoskeleton and the cytoskeleton was observed on matrix and within a Type I collagen gel.
Results:
MMP-14, -9, and -2 were localized to the podosome in the A7r5 smooth muscle cell and interactions were seen with these MMPs and the actin cytoskeleton. PDBu-stimulation induced increases in the protein abundance of the active forms of the MMPs and MMP-2 activity was increased. MMPs also interact with a-actin and not β-tubulin in the A7r5 cell. Galardin, also known as GM-6001, was shown to inhibit podosome formation and prevented MMP localization to the podosome. This broad spectrum MMP inhibitor also prevented collagen gel contraction and prevented cell adhesion and spreading of A7r5 cells within this collagen matrix.
Conclusion:
MMPs are important in the formation and function of podosomes in the A7r5 smooth muscle cell. MMPs interact with a-actin and not β-tubulin in the A7r5 cell. Podosomes play an important role in cell migration and understanding the function of podosomes can lead to insights into cancer metastasis and cardiovascular disease.
Insights
Matrix metalloproteinases (MMPs) are crucial for podosome formation and function in smooth muscle cells, interacting with actin. Understanding MMPs and podosomes offers insights into cancer metastasis and cardiovascular disease.
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Biology
Background:
- Matrix metalloproteinases (MMPs) are enzymes involved in extracellular matrix degradation.
- Podosomes are dynamic actin-rich structures crucial for cell adhesion, migration, and invasion.
- Smooth muscle cells play a role in vascular health and disease.
Purpose of the Study:
- To localize matrix metalloproteinase (MMP)-14, -9, and -2 in A7r5 smooth muscle cells.
- To investigate the interaction between these MMPs and the cytoskeleton under basal and stimulated conditions.
- To elucidate the role of MMPs in podosome formation and function.
Main Methods:
- Confocal microscopy to visualize MMP and tissue inhibitor of matrix metalloproteinases (TIMP) localization.
- Gel zymography to assess active MMP forms and activity.
- Use of actin and microtubule inhibitors to study cytoskeletal interactions.
- Observation of cytoskeleton within Type I collagen gels.
- Pharmacological inhibition of MMPs using Galardin (GM-6001).
Main Results:
- MMP-14, -9, and -2 were localized to podosomes in A7r5 cells, interacting with the actin cytoskeleton.
- Phorbol 12,13-dibutyrate (PDBu) stimulation increased active MMP forms and MMP-2 activity.
- MMPs interacted with alpha-actin, but not beta-tubulin.
- Galardin inhibited podosome formation, MMP localization, collagen gel contraction, and cell adhesion/spreading.
Conclusions:
- MMPs are integral to the formation and function of podosomes in smooth muscle cells.
- MMP interaction with the cytoskeleton involves alpha-actin.
- Podosomes are critical for cell migration, with implications for cancer metastasis and cardiovascular disease research.
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