Localization of fission yeast type II myosin, Myo2, to the cytokinetic actin ring is regulated by phosphorylation of a C-terminal coiled-coil domain and requires a functional septation initiation network
Localization of fission yeast type II myosin, Myo2, to the cytokinetic actin ring is regulated by phosphorylation of a C-terminal coiled-coil domain and requires a functional septation initiation network
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DOI：
10.1091/mbc.12.12.4044
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发表时间：
2001-12-01
影响因子：
3.3
通讯作者：
Hyams, JS
中科院分区：
文献类型：
--
作者：
Mulvihill, DP;Barretto, C;Hyams, JS
Myo 2截短融合到绿色荧光蛋白（GFP）定义了一个C-末端结构域的定位Myo 2的细胞动力学肌动蛋白环（CAR）。定位域包含两个预测的磷酸化位点。丝氨酸1518突变为丙氨酸（S（1518）A）消除了Myo 2定位，而在该位置具有谷氨酸的Myo 2（（SE）-E-1518）定位于CAR。GFP-Myo 2在25 ℃下在分隔起始激酶（SIN）突变体cdc 7 -24中形成环，但在36 ℃下不形成环。GFP-Myo 2S（1518）E环在36 ℃下在cdc 7 -24中持续存在，但在另一种SIN激酶突变体中不存在。为了进一步检查Myo 2和SIN途径之间的关系，将myo 2（+）的染色体拷贝与GFP融合（菌株myo 2-gc）。在限制性温度下，双突变体myo 2-gc cdc7.24和myo 2-gc cdc2.250中myo 2环的形成被消除。相反，在双突变myo 2-gc cdc 16 -116中SIN途径的激活导致Myo 2环的形成，其随后在36 ℃下塌陷。我们的结论是SIN途径，控制分裂酵母中的分隔也调节Myo 2环的形成和收缩。Cdc 7和Sid 2参与环的形成，在Cdc 7的情况下，通过Myo 2尾中单个丝氨酸残基的磷酸化。其他激酶和/或磷酸酶可以控制环收缩。
Myo2 truncations fused to green fluorescent protein (GFP) defined a C-terminal domain essential for the localization of Myo2 to the cytokinetic actin ring (CAR). The localization domain contained two predicted phosphorylation sites. Mutation of serine 1518 to alanine (S(1518)A) abolished Myo2 localization, whereas Myo2 with a glutamic acid at this position ((SE)-E-1518) localized to the CAR. GFP-Myo2 formed rings in the septation initiation kinase (SIN) mutant cdc7-24 at 25 degreesC but not at 36 degreesC. GFP-Myo2S(1518)E rings persisted at 36 degreesC in cdc7-24 but not in another SIN kinase mutant, sid2-250. To further examine the relationship between Myo2 and the SIN pathway, the chromosomal copy of myo2(+) was fused to GFP (strain myo2-gc). Myo2 ring formation was abolished in the double mutants myo2-gc cdc7.24 and myo2-gc sid2-250 at the restrictive temperature. In contrast, activation of the SIN pathway in the double mutant myo2-gc cdc16-116 resulted in the formation of Myo2 rings which subsequently collapsed at 36 degreesC. We conclude that the SIN pathway that controls septation in fission yeast also-regulates Myo2 ring formation and contraction. Cdc7 and Sid2 are involved in ring formation, in the case of Cdc7 by phosphorylation of a single serine residue in the Myo2 tail. Other kinases and/or phosphatases may control ring contraction.