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Calpain regulates actin remodeling during cell spreading
D A Potter1, J S Tirnauer, R Janssen
1Division of Hematology and Oncology, Tupper Research Institute, Department of Medicine, New England Medical Center, Boston, Massachusetts, USA. dpottervmhc@opal.tufts.edu
The Journal of Cell Biology
|June 13, 1998
Summary
Calpains are crucial for cell spreading and actin remodeling. Inhibiting calpain activity, by overexpressing calpastatin or using pharmacological inhibitors, prevents lamellipodia extension and cell spreading.
Area of Science:
- Cell Biology
- Biochemistry
Background:
- Calpains (calcium-dependent proteases) are implicated in actin cytoskeleton remodeling and cell migration.
- Their precise role in cell spreading requires direct investigation.
Purpose of the Study:
- To investigate the direct role of calpains in NIH-3T3 cell spreading.
- To analyze the effects of calpain inhibition on cell morphology and cytoskeletal dynamics.
Main Methods:
- Generated NIH-3T3 clonal cell lines overexpressing calpastatin (calpain inhibitor).
- Assessed cell morphology, spreading, cytoskeletal structure, and calpain activity in vitro and in situ.
- Utilized pharmacological calpain inhibitors (calpeptin, MDL 28,170).
Main Results:
- Calpastatin-overexpressing cells showed altered morphology, failed to extend lamellipodia, and exhibited abnormal filopodia.
- These cells displayed reduced calpain activity and impaired cell spreading.
- Pharmacological calpain inhibition also immediately blocked cell spreading.
- Ezrin protein levels increased significantly upon calpain inhibition.
Conclusions:
- Calpain activity is essential for normal cell spreading and actin remodeling.
- Calpain inhibition disrupts filopodia formation and lamellar extension, critical processes for cell movement.