Calcium inhibition of Physarum myosin as examined by the recombinant heavy mero-myosin.
Calcium inhibition of Physarum myosin as examined by the recombinant heavy mero-myosin.
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DOI：
10.1007/978-4-431-38453-3_22
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发表时间：
2007
影响因子：
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通讯作者：
H. Kawamichi;Ying Zhang;Mizuki Hino;A. Nakamura;Hideyuki Tanaka;L. Farkas;L. Nyitray;K. Kohama
中科院分区：
文献类型：
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作者：
H. Kawamichi;Ying Zhang;Mizuki Hino;A. Nakamura;Hideyuki Tanaka;L. Farkas;L. Nyitray;K. Kohama
多头绒泡菌的疟原虫表现出强烈的细胞质流动，每隔几分钟改变方向。这种振荡流由Ca2+调节，并被认为是由常规肌球蛋白驱动的，即，1，2在东京大学江桥教授实验室担任助理教授期间，本作者之一（K.K.）诱导疟原虫肌动球蛋白制剂或肌球蛋白B的超沉淀，以检测Ca 2+的影响。它不需要Ca2+就能超沉淀。当存在μM水平的Ca 2+时，超沉淀被抑制。3这种钙抑制与脊椎动物肌肉中肌动球蛋白的超沉淀完全相反，4并且我们预期这种抑制模式可能涉及植物细胞质流。2随着脊椎动物肌肉中多种非常规肌球蛋白如肌球蛋白I和V5的发现，在动物和植物界中，抑制模式显示在细胞运动中起作用。在这种情况下，肌球蛋白具有钙调蛋白（CaM）作为轻链，并通过Ca2+与CaM的相互作用进行调节，这对活性产生抑制作用。
Plasmodia of Physarum polycephalum shows vigorous cytoplasmic streaming by changing direction every few minutes. This oscillatory streaming is regulated by Ca2+and is thought to be driven by a conventional myosin, i.e., by a myosin II isoform.1,2 While working as an assistant professor in Professor Ebashi’s laboratory at the University of Tokyo, one of the present authors (K.K.) induced the superprecipitation of actomyosin preparation or myosin B from the plasmodia to examine the effect of Ca2+. It superprecipitated without requiring Ca2+. When Ca2+at μM level was present, the superprecipitation was inhibited.3 This calcium inhibition was quite the opposite of the superprecipitation of actomyosin from vertebrate muscles,4 and we expected that the inhibitory mode could be involved in the plant cytoplasmic streaming.2 With the finding of the diverse classes of unconventional myosin such as myosin I and V5 in vertebrate muscles, the inhibitory mode was shown to play a role in cell motility in both animal and plant kingdoms. In this case the myosins have calmodulin (CaM) as the light chains and are regulated by interaction of Ca2+with CaM, which exerts an inhibitory effect on activity.5