Kreis T E, Geiger B, Schlessinger J
Cell. 1982 Jul;29(3):835-45. doi: 10.1016/0092-8674(82)90445-7.
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.
将罗丹明标记的肌动蛋白显微注射到活的胚胎鸡砂囊细胞中后，它会与细胞特有的细胞骨架结构相结合。在这些区域，通过荧光漂白恢复（FPR）测量在体内测定了罗丹明标记肌动蛋白（rh-actin）的平移扩散系数（D）。根据其迁移率检测到两类肌动蛋白分子：在应力纤维和粘着斑中恢复半衰期为5 - 10分钟的rh-actin（在FPR测量的时间尺度上是不可移动的）以及在细胞质和前缘中扩散系数D = 2 - 3×10⁻⁹ cm²/秒的rh-actin。无论短片段还是整个结构被光漂白，应力纤维上的缓慢恢复都表现出相似的动力学，这表明恢复主要是通过与周围可扩散的肌动蛋白交换而发生的。我们提出，在活细胞中肌动蛋白的可溶性池和细胞骨架池之间存在稳态平衡。
