Protein kinase involved in flagellar-length control
Protein kinase involved in flagellar-length control
复制标题
DOI：
10.1128/ec.2.4.769-777.2003
复制
发表时间：
2003-08-01
期刊：
影响因子：
--
通讯作者：
Grünfelder, CG
中科院分区：
文献类型：
--
作者：
Wiese, M;Kuhn, D;Grünfelder, CG
在其生活史中，寄生原生动物墨西哥利什曼原虫（Leishmania mexicana）从有鞭毛的前鞭毛体（promastigote）分化为携带退化鞭毛的无鞭毛体（amastigote）。除了生物化学变化，这一过程涉及整个细胞形态的变化，包括鞭毛缩短。一个丝裂原活化蛋白激酶激酶同源物指定LmxMKK被确定在同源性筛选，并发现是至关重要的参与鞭毛组装和细胞大小的调节。LmxMKK仅在前鞭毛体阶段表达，并且可能受到磷酸化等翻译后机制的调节。单拷贝基因的缺失突变体显示能动鞭毛的长度显著减少，并且缺乏鞭毛旁杆，这是动质体鞭毛中与轴丝相邻的结构。此外，一部分细胞的轴丝结构的扰动。缺失突变体与野生型基因互补恢复了典型的前鞭毛体形态。我们建议，LmxMKK影响顺行鞭毛内运输，以保持鞭毛长度在利什曼原虫promastigotes，因此，它是已知的第一个蛋白激酶参与细胞器组装。
During its life cycle, the parasitic protozoon Leishmania mexicana differentiates from a flagellated form, the promastigote, to an amastigote form carrying a rudimentary flagellum. Besides biochemical changes, this process involves a change in overall cell morphology including flagellar shortening. A mitogen-activated protein kinase kinase homologue designated LmxMKK was identified in a homology screening and found to be critically involved in the regulation of flagellar assembly and cell size. LmxMKK is exclusively expressed in the promastigote stage and is likely to be regulated by posttranslational mechanisms such as phosphorylation. A deletion mutant for the single-copy gene revealed motile flagella dramatically reduced in length and lacking the paraflagellar rod, a structure adjacent to the axoneme in kinetoplastid flagella. Moreover, a fraction of the cells showed perturbance of the axonemal structure. Complementation of the deletion mutant with the wild-type gene restored typical promastigote morphology. We propose that LmxMKK influences anterograde intraflagellar transport to maintain flagellar length in Leishmania promastigotes; as such, it is the first protein kinase known to be involved in organellar assembly.