Reduced cell migration and disruption of the actin cytoskeleton in calpain-deficient embryonic fibroblasts

Nathalie Dourdin, Amit K. Bhatt, Previn Dutt, Peter A. Greer, J. Simon C. Arthur, John S. Elce, Anna Huttenlocher

    Research output: Contribution to journalArticle

    205 Citations (Scopus)

    Abstract

    The physiological functions and substrates of the calcium-dependent protease calpain remain only partly understood. The µ- and m-calpains consist of a µ- or m-80-kDa large subunit (genes Capn1 and Capn2), and a common 28-kDa small subunit (Capn4). To assess the role of calpain in migration, we used fibroblasts obtained from Capn4-/- mouse embryos. The cells lacked calpain activity on casein zymography and did not generate the characteristic calpain-generated spectrin breakdown product that is observed in wild-type cells. Capn4-/- cells had decreased migration rates and abnormal organization of the actin cytoskeleton with a loss of central stress fibers. Interestingly, these cells extended numerous thin projections and displayed delayed retraction of membrane protrusions and filopodia. The number of focal adhesions was decreased in Capn4-/- cells, but the cells had prominent vinculin-containing focal complexes at the cell periphery. The levels of the focal adhesion proteins, alpha-actinin, focal adhesion kinase (FAK), spectrin, talin, and vinculin, were the same in Capn4+/+ and Capn4-/- cells. FAK, a-actinin, and vinculin were not cleaved in either cell type plated on fibronectin. However, proteolysis of the focal complex component, talin, was detected in the wild-type cells but not in the Capn4-/- cells, suggesting that calpain cleavage of talin is important during cell migration. Moreover, talin cleavage was again observed when calpain activity was partially restored in Capn4-/- embryonic fibroblasts by stable transfection with a vector expressing the rat 28-kDa calpain small subunit. The results demonstrate unequivocally that calpain is a critical regulator of cell migration and of the organization of the actin cytoskeleton and focal adhesions.

    Original languageEnglish
    Pages (from-to)48382-48388
    Number of pages7
    JournalJournal of Biological Chemistry
    Volume276
    Issue number51
    DOIs
    Publication statusPublished - 21 Dec 2001

    Keywords

    • Talin
    • Cell Movement
    • Animals
    • Mice
    • Hydrolysis
    • Fibroblasts
    • Cytoskeleton
    • Rats
    • Actins
    • Calpain
    • Antigens, Polyomavirus Transforming
    • Cell Line, Transformed
    • Embryo, Mammalian
    • Cell Line

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