title: Subcellular distribution of rhodamine-actin microinjected into living fibroblastic cells.
abstract: The time course and pattern of incorporation of rhodamine-labeled actin microinjected into cultured fibroblastic cells were examined by fluorescence microscopy. Following microinjection, the fluorescent probe was incorporated rapidly into ruffling membranes, and within 5 min faintly fluorescent stress fibers were observed. Levels of fluorescence in ruffling membranes then tended to remain constant while fluorescence of the stress fibers continued to increase until approximately 20-min postinjection. Small, discrete regions of some microinjected cells displayed high levels of fluorescence that appeared initially approximately 5-10 min postinjection. I observed these small areas of intense fluorescence frequently near the cell periphery, which corresponded to focal contacts when examined with interference reflection optics. The results of this study show that a relationship exists between patterns of fluorescent actin incorporation in these cells and cellular areas or structures presumed to play a role in cell movement. These findings suggest that actin within stress fibers and the microfilament network of ruffling membranes undergoes a rapid turnover that may relate directly to the motility of the cell.
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D002465:Cell Movement; D002478:Cells, Cultured; D002642:Chick Embryo; D003593:Cytoplasm / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism*; D005347:Fibroblasts; D007700:Kinetics; D008845:Microinjections; D008856:Microscopy, Fluorescence; D012235:Rhodamines
chemical_list: D000199:Actins; D012235:Rhodamines