Differential Dynamics of α5 Integrin, Paxillin, and α-Actinin during Formation and Disassembly of Adhesions in Migrating Cells
| Autor: | Christina M. Laukaitis, Alan F. Horwitz, Karen Donais, Donna J. Webb |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Intracellular Fluid
Macromolecular Substances Recombinant Fusion Proteins Green Fluorescent Proteins Integrin CHO Cells Integrin alpha5 macromolecular substances Actinin Cell Membrane Structures Cell Line 03 medical and health sciences 0302 clinical medicine Antigens CD Cell Movement Cricetinae Receptors Transferrin Cell Adhesion endocytosis Animals Pseudopodia Transport Vesicles Cell adhesion Cytoskeleton Paxillin Fluorescent Dyes 030304 developmental biology 0303 health sciences Microscopy Video biology membrane protrusions Cell Biology Phosphoproteins Cell biology Cytoskeletal Proteins Luminescent Proteins Protein Transport Endocytic vesicle vesicle trafficking biology.protein Original Article Lamellipodium 030217 neurology & neurosurgery |
| Zdroj: | The Journal of Cell Biology |
| ISSN: | 1540-8140 0021-9525 |
| DOI: | 10.1083/jcb.153.7.1427 |
| Popis: | To investigate the mechanisms by which adhesions form and disperse in migrating cells, we expressed alpha 5 integrin, alpha-actinin, and paxillin as green fluorescent protein (GFP) fusions. All localized with their endogenous counterparts and did not perturb migration when expressed at moderate levels. alpha 5-GFP also rescued the adhesive defects in CHO B2 cells, which are alpha 5 integrin deficient. In ruffling cells, alpha 5-GFP and alpha-actinin--GFP localized prominently at the leading edge in membrane protrusions. Of the three GFP fusion proteins that we examined, paxillin was the first component to appear visibly organized in protrusive regions of the cell. When a new protrusion formed, the paxillin appeared to remodel from older to newer adhesions at the leading edge. alpha-Actinin subsequently entered adhesions, which translocated toward the cell center, and inhibited paxillin turnover. The new adhesions formed from small foci of alpha-actinin--GFP and paxillin-GFP, which grew in size. Subsequently, alpha 5 integrin entered the adhesions to form visible complexes, which served to stabilize the adhesions. alpha 5-GFP also resided in endocytic vesicles that emanated from the leading edge of protrusions. Integrin vesicles at the cell rear moved toward the cell body. As cells migrated, alpha 5 vesicles also moved from a perinuclear region to the base of the lamellipodium. The alpha 5 vesicles colocalized with transferrin receptor and FM 4-64 dye. After adhesions broke down in the rear, alpha 5-GFP was found in fibrous structures behind the cell, whereas alpha-actinin--GFP and paxillin-GFP moved up the lateral edge of retracting cells as organized structures and then dissipated. |
| Databáze: | OpenAIRE |
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