Identification of two type V myosins in fission yeast, one of which functions in polarized cell growth and moves rapidly in the cell
Identification of two type V myosins in fission yeast, one of which functions in polarized cell growth and moves rapidly in the cell
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DOI：
10.1091/mbc.12.5.1367
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发表时间：
2001-05-01
影响因子：
3.3
通讯作者：
Mabuchi, I
中科院分区：
文献类型：
--
作者：
Motegi, F;Arai, R;Mabuchi, I
我们表征了新的裂殖酵母基因myo 4（+）和myo 5（+），这两个基因都编码肌球蛋白-V重链。myo 4的破坏导致细胞生长缺陷，并导致整个细胞质中分泌囊泡的异常积累。突变细胞比正常细胞圆，但细胞极化的位点仍然建立。细胞末端的伸长和分隔的完成需要比野生型细胞更多的时间，这表明Myo 4在细胞末端和分隔期间的极化生长中起作用。与这一结论相一致，Myo 4定位在生长的细胞末端、内侧F-肌动蛋白环和隔膜周围，为一簇点状结构。在活细胞中，带有绿色荧光蛋白标记的Myo 4在这些区域周围快速移动。Myo 4的定位和运动依赖于F-肌动蛋白电缆和它的运动活性，但似乎是独立的微管。此外，Myo 4的运动活性对其功能至关重要。这些结果表明，Myo 4参与极化细胞生长的分泌囊泡沿着的F-肌动蛋白电缆周围的网站极化。相比之下，myo 5空细胞的表型与野生型细胞的表型无法区分。这些数据和其他数据表明，Myo 5的作用与Myo 4不同。
We characterized the novel Schizosaccharomyces pombe genes myo4(+) and myo5(+), both of which encode myosin-V heavy chains. Disruption of myo4 caused a defect in cell growth and led to an abnormal accumulation of secretory vesicles throughout the cytoplasm. The mutant cells were rounder than normal, although the sites for cell polarization were still established. Elongation of the cell ends and completion of septation required more time than in wild-type cells, indicating that Myo4 functions in polarized growth both at the cell ends and during septation. Consistent with this conclusion, Myo4 was localized around the growing cell ends, the medial F-actin ring, and the septum as a cluster of dot structures. In living cells, the dots of green fluorescent protein-tagged Myo4 moved rapidly around these regions. The localization and movement of Myo4 were dependent on both F-actin cables and its motor activity but seemed to be independent of microtubules. Moreover, the motor activity of Myo4 was essential for its function. These results suggest that Myo4 is involved in polarized cell growth by moving with a secretory vesicle along the F-actin cables around the sites for polarization. In contrast, the phenotype of myo5 null cells was indistinguishable from that of wild-type cells. This and other data suggest that Myo5 has a role distinct from that of Myo4.