The role of polar localization in the function of an essential Caulobacter crescentus tyrosine kinase
The role of polar localization in the function of an essential Caulobacter crescentus tyrosine kinase
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DOI：
10.1111/j.1365-2958.2005.04652.x
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发表时间：
2005-06-01
影响因子：
3.6
通讯作者：
Newton, A
中科院分区：
文献类型：
--
作者：
Sciochetti, SA;Ohta, N;Newton, A
DivL 是新月柄杆菌中的一种重要酪氨酸激酶，控制细胞分裂周期的早期步骤。我们在这里表明，DivL 在 S 期动态地定位于茎远端细胞极，并且较少频繁地定位于茎细胞极。随后，激酶在分裂后期从细胞极释放，并保持分散在新分裂的子代茎和群细胞中。 DivL-GFP 融合蛋白中 DivL 的突变分析表明，保守四螺旋束中的极端 C 末端和残基（即磷酸化 - 二聚化结构域）对于定位非常重要。我们推测核心催化结构域的四螺旋束可能充当“定位机制”的识别位点。出乎意料的是，C 端定位序列发生突变的 DivL 蛋白和完整的催化结构域能够有效地补充 divL 无效突变。因此，DivL 的亚细胞定位对其细胞分裂调节功能来说并不是必需的。然而，DivL 对细胞分裂的调节确实取决于其在细胞膜中的定位。
DivL is an essential tyrosine kinase in Caulobacter crescentus that controls an early step in the cell division cycle. We show here that DivL dynamically localizes to the stalk-distal cell pole and less frequently to the stalked cell pole during the S-phase. The kinase is subsequently released from the cell poles late in division and remains dispersed in the newly divided progeny stalk and swarmer cells. Mutational analysis of DivL in a DivL-GFP fusion protein demonstrated that the extreme C-terminus and residues in the conserved four-helix bundle, which is the phosphorylation - dimerization domain, are important for localization. We speculate that the four-helix bundle of the core catalytic domain may serve as a recognition site for the 'localization machinery'. Unexpectedly, a DivL protein with mutations in the C-terminal localization sequence, and an intact catalytic domain, efficiently complemented a divL null mutation. Thus, subcellular localization of DivL is not essential to its function in cell division regulation. Regulation of cell division by DivL does, however, depend on its localization in the cell membrane.