Identification and Characterization of Higher Plant Myosins Responsible for Cytoplasmic Streaming
Identification and Characterization of Higher Plant Myosins Responsible for Cytoplasmic Streaming
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负责细胞质流的高等植物肌球蛋白的鉴定和表征
DOI：
10.1007/pl00013962
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发表时间：
2000
影响因子：
2.8
通讯作者：
E. Yokota
中科院分区：
文献类型：
--
作者：
E. Yokota
在体外使用这些肌球蛋白，以及使用针对每个重链的抗血清进行定位研究，我们认为这两种肌球蛋白都是产生高等植物细胞胞质流动动力的分子马达。170 kDa的肌球蛋白不仅在体细胞中表达，而且在萌发的花粉中也有表达。相比之下，175 kDa的肌球蛋白只分布在体细胞中。在花粉管生长的顶端区域，已经证明以顶端为中心的钙梯度对于花粉管的生长和定向是必不可少的。这一区域的细胞质流动已被证明被高浓度的钙离子灭活。170kDa肌球蛋白的体外运动活性被低水平的钙离子(μM)通过其CaM轻链抑制，这表明这种抑制是抑制花粉管顶端附近细胞质流动的机制之一。当钙离子浓度高于10−6M时，175kDa肌球蛋白的体外运动活性也被抑制。已有研究表明，胞质内钙离子浓度的升高导致胞质流动的停止，甚至在体细胞中也是如此。因此，肌球蛋白的运动活性对钙的敏感性似乎是钙离子导致胞质流动停止的一般分子基础。
in vitro using these myosins and of localization studies using antiserum raised against each heavy chain, we suggested that both myosins are molecular motors for generating the motive force for cytoplasmic streaming in higher plant cells. The 170-kDa myosin is expressed not only in somatic cells but also in germinating pollen. In contrast, the 175-kDa myosin is distributed only in somatic cells. In the tip region of growing pollen tubes, it has been demonstrated that a tip-focused Ca2+ gradient is indispensable for growth and tube orientation. Cytoplasmic streaming in this region has been shown to be inactivated by high concentrations of Ca2+. The motile activity in vitro of 170-kDa myosin is suppressed by low (μM) levels of Ca2+ through its CaM light chain, suggesting that this suppression is one of the mechanisms for inactivating cytoplasmic streaming near the tip region of pollen tubes. The motile activity in vitro of 175-kDa myosin is also inhibited by Ca2+ at concentrations higher than 10−6M. It has been revealed that the elevation of cytosolic Ca2+ concentrations causes the cessation of cytoplasmic streaming even in somatic cells. Therefore, Ca2+-sensitivity of the motile activity of myosin appears to be a general molecular basis for Ca2+-induced cessation of cytoplasmic streaming.
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影响因子：
2.7
作者：
Messerli, MA;Créton, R;Robinson, KR
通讯作者：
Robinson, KR
影响因子：
64.5
作者：
CHENEY, RE;OSHEA, MK;MOOSEKER, MS
通讯作者：
MOOSEKER, MS
Ca2+ 通过三个或四个钙调蛋白轻链刺激刷状缘肌球蛋白 I 的 Mg2(+)-ATP 酶活性，但通过少于两个结合的钙调蛋白轻链来抑制。
DOI：
--
发表时间：
1991
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Swanljung-Collins,H;Collins,JH
通讯作者：
Collins,JH
影响因子：
11.6
作者：
PIERSON, ES;MILLER, DD;HEPLER, PK
通讯作者：
HEPLER, PK
新型 130 kDa 大鼠肝脏肌球蛋白-1 将使肌动蛋白丝易位。
影响因子：
--
作者：
Williams,R;Coluccio,LM
通讯作者：
Coluccio,LM