Mechanism of regulation of actin polymerization by Physarum profilin.
Mechanism of regulation of actin polymerization by Physarum profilin.
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DOI：
10.1083/jcb.98.6.1919
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发表时间：
1984-06
期刊：
影响因子：
--
通讯作者：
Hatano S
中科院分区：
文献类型：
--
作者：
Ozaki K;Hatano S
绒泡菌Profilin以浓度依赖的方式降低F-肌动蛋白的成核率和伸长率，并降低稳态时肌动蛋白的聚合程度。Profilin的加入提高了肌动蛋白聚合的表观临界浓度。这些结果可以用绒泡菌Profilin与G-肌动蛋白形成1：1的络合物并降低可用于聚合的肌动蛋白浓度的观点来解释。根据G-肌动蛋白的聚合动力学和F-肌动蛋白核的伸长动力学，以及在Profilin存在下的表观临界浓度的增加，估算了Profilin与G-肌动蛋白结合的解离常数。在生理离子条件下，绒泡菌和肌动蛋白结合的解离常数分别为1.4-3.7微米和11.3-28.5微米。当Profilin加入到F-肌动蛋白溶液中时，Profilin与与F-肌动蛋白共存的G-肌动蛋白结合，然后G-肌动蛋白从F-肌动蛋白中解离出来，以补偿游离G-肌动蛋白浓度的下降并使其在临界浓度下保持不变。在稳定状态下，临界浓度的游离G-肌动蛋白不仅与F-肌动蛋白处于平衡状态，而且与Profilin-G-肌动蛋白复合体处于平衡状态。化学交联法直观地显示了Profilin与G-肌动蛋白形成络合物的化学计量比为1：1。
Physarum profilin reduces the rates of nucleation and elongation of F- actin and also reduces the extent of polymerization of actin at the steady state in a concentration-dependent fashion. The apparent critical concentration for polymerization of actin is increased by the addition of profilin. These results can be explained by the idea that Physarum profilin forms a 1:1 complex with G-actin and decreases the concentration of actin available for polymerization. The dissociation constant for binding of profilin to G-actin is estimated from the kinetics of polymerization of G-actin and elongation of F-actin nuclei and from the increase of apparent critical concentration in the presence of profilin. The dissociation constants for binding of Physarum profilin to Physarum and muscle actins under physiological ionic conditions are in the ranges of 1.4-3.7 microM and 11.3-28.5 microM, respectively. When profilin is added to an F-actin solution, profilin binds to G-actin which co-exists with F-actin, and then G- actin is dissociated from F-actin to compensate for the decrease of the concentration of free G-actin and to keep it constant at the critical concentration. At the steady state, free G-actin of the critical concentration is in equilibrium not only with F-actin but also with profilin-G-actin complex. The stoichiometry of 1:1 for the formation of complex between profilin and G-actin is directly shown by means of chemical cross-linking.
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DOI：
10.2307/2480903
发表时间：
1936-01-01
期刊：
BULL TORREY BOT CLUB
影响因子：
--
作者：
CAMP, W. G.
通讯作者：
CAMP, W. G.
影响因子：
2.9
作者：
HASEGAWA, T;TAKAHASHI, S;HATANO, S
通讯作者：
HATANO, S
影响因子：
2.9
作者：
MOCKRIN, SC;KORN, ED
通讯作者：
KORN, ED
影响因子：
--
作者：
SUGINO, H;HATANO, S
通讯作者：
HATANO, S
影响因子：
7.8
作者：
Hubbard, B D;Lazarides, E
通讯作者：
Lazarides, E