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Dynamin participates in focal extracellular matrix degradation by invasive cells
Massimiliano Baldassarre1, Arsenio Pompeo, Galina Beznoussenko
1Department of Cell Biology and Oncology, Istituto di Ricerche Farmacologiche Mario Negri, Consorzio Mario Negri Sud, S. Maria Imbaro (Chieti), 66030 Italy.
Abstract:
The degradation of extracellular matrix (ECM) by matrix metalloproteases is crucial in physiological and pathological cell invasion alike. Degradation occurs at specific sites where invasive cells make contact with the ECM via specialized plasma membrane protrusions termed invadopodia. Herein, we show that the dynamin 2 (Dyn2), a GTPase implicated in the control of actin-driven cytoskeletal remodeling events and membrane transport, is necessary for focalized matrix degradation at invadopodia. Dynamin was inhibited by using two approaches: 1) expression of dominant negative GTPase-impaired or proline-rich domain-deleted Dyn2 mutants; and 2) inhibition of the dynamin regulator calcineurin by cyclosporin A. In both cases, the number and extension of ECM degradation foci were drastically reduced. To understand the site and mechanism of dynamin action, the cellular structures devoted to ECM degradation were analyzed by correlative confocal light-electron microscopy. Invadopodia were found to be organized into a previously undescribed ECM-degradation structure consisting of a large invagination of the ventral plasma membrane surface in close spatial relationship with the Golgi complex. Dyn2 seemed to be concentrated at invadopodia.
Insights
Dynamin 2 (Dyn2) is essential for focalized extracellular matrix (ECM) degradation at invadopodia, a process vital for cell invasion. Inhibiting Dyn2 significantly reduced ECM degradation sites, highlighting its role in cell motility.
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Biology
Background:
- Extracellular matrix (ECM) degradation by matrix metalloproteases is critical for cell invasion in both normal and disease states.
- Invasive cells utilize specialized plasma membrane protrusions called invadopodia to interact with and degrade the ECM.
Purpose of the Study:
- To investigate the role of dynamin 2 (Dyn2) in focalized ECM degradation at invadopodia.
- To elucidate the mechanism and cellular localization of Dyn2 during ECM degradation.
Main Methods:
- Inhibition of dynamin 2 (Dyn2) using dominant-negative mutants and calcineurin inhibition with cyclosporin A.
- Analysis of ECM degradation foci using correlative confocal light-electron microscopy.
- Localization studies of Dyn2 within invadopodia.
Main Results:
- Inhibition of Dyn2 function drastically reduced the number and extension of ECM degradation foci.
- Dyn2 was found to be concentrated at invadopodia.
- Invadopodia were identified as a novel ECM-degradation structure involving ventral plasma membrane invagination near the Golgi complex.
Conclusions:
- Dynamin 2 (Dyn2) is a necessary component for localized ECM degradation at invadopodia.
- Dyn2 plays a crucial role in regulating the formation and function of invadopodia-mediated ECM degradation structures.
- These findings reveal a previously undescribed invadopodia organization and Dyn2's involvement in ECM remodeling during cell invasion.