Related Experiment Videos
Calpain is required for MMP-2 and u-PA expression in SV40 large T-antigen-immortalized cells
Lynne-Marie Postovit1, Previn Dutt, Nathalie Dourdin
1Department of Anatomy and Cell Biology, Queen's University, Kingston, Ont., Canada K7L 3N6.
Abstract:
The absence of both mu- and m-calpain activity, caused by disruption of the capn4 gene in mice, retarded migration, and disrupted the cytoskeleton, both in primary capn4(-/-) embryonic fibroblasts (mEF) and in capn4(-/-) mEF immortalized with SV40 large T-antigen (TAg). These results are thought to reflect the role of calpain in integrin signaling to the cytoskeleton. The integrins are also involved, together with matrix metalloproteinases (MMP) and plasminogen activators (PA), in cellular invasion. This study therefore aimed to establish whether links exist between the calpain, MMP, and PA systems, using both primary and TAg-immortalized capn4(+/+) and capn4(-/-) embryonic fibroblasts. Both Matrigel invasion, and expression of MMP-2 and u-PA activities, correlated with calpain expression in TAg-containing cells, but not in primary cells. MMP-2 mRNA synthesis also correlated with calpain expression in the presence of TAg, but u-PA mRNA synthesis was not so correlated. The results suggest that calpain acquires new regulatory roles in the presence of TAg. Calpain is also required for v-Src-mediated transformation. It appears that calpain may have previously unsuspected roles in oncogenic transformation.
Insights
Calpain activity, essential for cell migration and cytoskeleton integrity, interacts with matrix metalloproteinases and plasminogen activators. Its roles in cell invasion and oncogenic transformation are newly revealed, especially in TAg-immortalized cells.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Calpain activity is crucial for cell migration and cytoskeleton organization.
- Integrins, matrix metalloproteinases (MMPs), and plasminogen activators (PAs) are involved in cellular invasion.
- The interplay between calpain, MMPs, and PAs is not fully understood.
Purpose of the Study:
- To investigate the relationship between calpain, MMP, and PA systems.
- To determine if calpain influences cellular invasion and MMP/PA activity.
- To explore calpain's role in oncogenic transformation.
Main Methods:
- Utilized primary and SV40 large T-antigen (TAg)-immortalized capn4(+/+) and capn4(-/-) embryonic fibroblasts.
- Assessed Matrigel invasion, MMP-2 and u-PA activities, and their corresponding mRNA synthesis.
- Examined calpain's role in v-Src-mediated transformation.
Main Results:
- Absence of calpain activity in capn4(-/-) cells impaired migration and disrupted the cytoskeleton.
- In TAg-immortalized cells, Matrigel invasion and MMP-2/u-PA activities correlated with calpain expression.
- MMP-2 mRNA synthesis correlated with calpain in TAg cells, but u-PA mRNA synthesis did not.
- Calpain is required for v-Src-mediated transformation.
Conclusions:
- Calpain plays a role in integrin signaling to the cytoskeleton.
- Calpain appears to acquire new regulatory functions in the presence of TAg.
- Calpain has previously unrecognized roles in oncogenic transformation.