Mobility of microinjected rhodamine actin within living chicken gizzard cells determined by fluorescence photobleaching recovery.
Rhodamine-labeled actin microinjected into living embryonic chicken gizzard cells became associated with its characteristic cytoskeletal structures. In these domains the translational diffusion coefficients (D) of rh-actin were determined in vivo by fluorescence photobleaching recovery (FPR) measurements. Two classes of actin molecules with respect to its mobilities were detected: rh-actin with a half-time of recovery of 5-10 min in stress fibers and focal contacts (immobile on the time-scale of FPR measurements) and rh-actin with D = 2-3 X 10(-9) cm2/sec in the cytoplasm and leading lamellae. The slow recovery on stress fibers exhibited similar kinetics whether a short segment or the entire structure were photobleached, indicating that recovery occurs predominantly by exchange with the surrounding diffusable actin. We propose that a steady-state equilibrium between the soluble and cytoskeletal pool of actin exists in living cells.
D000199:Actins / Q000502:physiology*; D000818:Animals; D002448:Cell Adhesion; D002451:Cell Compartmentation; D002465:Cell Movement; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000502:physiology; D003599:Cytoskeleton / Q000502:physiology*; D000070559:Gizzard, Non-avian; D008856:Microscopy, Fluorescence / Q000379:methods; D012235:Rhodamines
D000199:Actins; D012235:Rhodamines