Polymerizing actin fibers position integrins primed to probe for adhesion sites.
Migrating cells extend protrusions, probing the surrounding matrix in search of permissive sites to form adhesions. We found that actin fibers polymerizing along the leading edge directed local protrusions and drove synchronous sideways movement of beta1 integrin adhesion receptors. These movements lead to the clustering and positioning of conformationally activated, but unligated, beta1 integrins along the leading edge of fibroblast lamellae and growth cone filopodia. Thus, rapid actin-based movement of primed integrins along the leading edge suggests a "sticky fingers" mechanism to probe for new adhesion sites and to direct migration.
Galbraith
Catherine G
CG
National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
Yamada
Kenneth M
KM
Galbraith
James A
JA
D000199:Actins / Q000502:physiology*; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000502:physiology; D005353:Fibronectins / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D019012:Integrin beta1 / Q000502:physiology*; D051379:Mice; D008840:Microfilament Proteins / Q000378:metabolism; D041681:NIH 3T3 Cells; D010750:Phosphoproteins / Q000378:metabolism; D011485:Protein Binding; D011554:Pseudopodia / Q000378:metabolism; D000098662:Vasodilator-Stimulated Phosphoprotein
D000199:Actins; D015815:Cell Adhesion Molecules; D005353:Fibronectins; D019012:Integrin beta1; D008840:Microfilament Proteins; D010750:Phosphoproteins; D000098662:Vasodilator-Stimulated Phosphoprotein; D049452:Green Fluorescent Proteins