Yeast myosin light chain, Mlc1p, interacts with both IQGAP and class II myosin to effect cytokinesis.
Yeast myosin light chain, Mlc1p, interacts with both IQGAP and class II myosin to effect cytokinesis.
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发表时间：
2000-12
影响因子：
4
通讯作者：
James R. Boyne;Hirzun Mohd Yosuf;P. Bieganowski;Charles Brenner;Clive Price
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文献类型：
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作者：
James R. Boyne;Hirzun Mohd Yosuf;P. Bieganowski;Charles Brenner;Clive Price
肌球蛋白轻链是酿酒酵母IQGAP蛋白编码基因中对温度敏感的突变的剂量抑制因子。在有丝分裂中，这两种蛋白都定位在芽颈，尽管Mlc1p的定位先于Iqg1p。在细胞周期的G(1)期和G(2)期，Mlc1p也存在于初芽部位和生长的芽尖。显性的负GST-Mlc1p融合蛋白特异性地阻止细胞质分裂并阻止Iqg1p定位到芽颈，Mlc1p的耗尽也是如此。这些数据支持这两种蛋白质之间的直接相互作用，免疫沉淀实验证实了这一预测。Mlc1p还被证明与第二类常规肌球蛋白(Myo1p)相互作用。Mlc1p和Iqg1p之间的相互作用可以从Mlc1p/Myo1p的相互作用中分离出来。Mlc1p在芽颈的定位和维持不依赖于肌动蛋白、Myo1p和Iqg1p。因此，Mlc1p的功能是招募Iqg1p，进而将肌动蛋白聚集到肌球蛋白环上，并且在环收缩过程中，Mlc1p也是Myo1p功能所必需的。
MLC1 (myosin light chain) acts as a dosage suppressor of a temperature sensitive mutation in the gene encoding the S. cerevisiae IQGAP protein. Both proteins localize to the bud neck in mitosis although Mlc1p localisation precedes Iqg1p. Mlc1p is also found at the incipient bud site in G(1) and the growing bud tip during S and G(2) phases of the cell cycle. A dominant negative GST-Mlc1p fusion protein specifically blocks cytokinesis and prevents Iqg1p localisation to the bud neck, as does depletion of Mlc1p. These data support a direct interaction between the two proteins and immunoprecipitation experiments confirm this prediction. Mlc1p is also shown to interact with the class II conventional myosin (Myo1p). All three proteins form a complex, however, the interaction between Mlc1p and Iqg1p can be separated from the Mlc1p/Myo1p interaction. Mlc1p localisation and maintenance at the bud neck is independent of actin, Myo1p and Iqg1p. It is proposed that Mlc1p therefore functions to recruit Iqg1p and in turn actin to the actomyosin ring and that it is also required for Myo1p function during ring contraction.