Actin dynamics in living mammalian cells.
The actin cytoskeleton maintains the cellular architecture and mediates cell movements. To explore actin cytoskeletal dynamics, the enhanced green fluorescent protein (EGFP) was fused to human &bgr ;-actin. The fusion protein was incorporated into actin fibers which became depolymerized upon cytochalasin B treatment. This functional EGFP-actin construct enabled observation of the actin cytoskeleton in living cells by time lapse fluorescence microscopy. Stable expression of the construct was obtained in mammalian cell lines of different tissue origins. In stationary cells, actin rich, ring-like structured 'actin clouds' were observed in addition to stress fibers. These ruffle-like structures were found to be involved in the reorganization of the actin cytoskeleton. In migratory cells, EGFP-actin was found in the advancing lamellipodium. Immobile actin spots developed in the lamellipodium and thin actin fibers formed parallel to the leading edge. Thus EGFP-actin expressed in living cells unveiled structures involved in the dynamics of the actin cytoskeleton.
Ballestrem
C
C
Department of Pathology, Centre Medical Universitaire, Geneva, Switzerland.
Wehrle-Haller
B
B
Imhof
B A
BA
D016475:3T3 Cells; D008841:Actin Cytoskeleton / Q000235:genetics / Q000378:metabolism; D000199:Actins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D016466:CHO Cells; D002465:Cell Movement / Q000502:physiology; D006224:Cricetinae; D003599:Cytoskeleton / Q000502:physiology; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured
D000199:Actins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins