An intramolecular interaction between the FHA domain and a coiled coil negatively regulates the kinesin motor KIK1A
An intramolecular interaction between the FHA domain and a coiled coil negatively regulates the kinesin motor KIK1A
复制标题
DOI：
10.1038/sj.emboj.7600164
复制
发表时间：
2004-04-07
期刊：
影响因子：
11.4
通讯作者：
Kim, E
中科院分区：
文献类型：
--
作者：
Lee, JR;Shin, H;Kim, E
不积极参与运输货物的马达蛋白应在货物装载位点保持无活性，以节省能量并保持可用于装载。KIF1A/Unc104是一种单体驱动蛋白，已知在高蛋白浓度下二聚化为进行性马达。然而，单体稳定化和单体向二聚体转变的分子机制还没有很好地理解。在这里，我们报告了一个分子内相互作用KIF1A之间的叉头相关（FHA）域和卷曲螺旋域（CC2）紧接着FHA域。通过FHA或CC2结构域中的点突变破坏这种相互作用导致KIF1A在活的培养神经元的外周中显著积累，并增强微管（MT）结合和KIF1A的自多聚化。此外，在预测的柔性铰链中引起刚性的点突变破坏了分子内FHA-CC2相互作用，并增加了MT结合和KIF1A的外周蓄积。这些结果表明，分子内的FHA-CC2相互作用负调控KIF1A活性，抑制MT结合和二聚化的KIF1A，并指出一个新的作用的FHA域的调节驱动蛋白马达。
Motor proteins not actively involved in transporting cargoes should remain inactive at sites of cargo loading to save energy and remain available for loading. KIF1A/ Unc104 is a monomeric kinesin known to dimerize into a processive motor at high protein concentrations. However, the molecular mechanisms underlying monomer stabilization and monomer-to-dimer transition are not well understood. Here, we report an intramolecular interaction in KIF1A between the forkhead-associated (FHA) domain and a coiled-coil domain (CC2) immediately following the FHA domain. Disrupting this interaction by point mutations in the FHA or CC2 domains leads to a dramatic accumulation of KIF1A in the periphery of living cultured neurons and an enhancement of the microtubule (MT) binding and self-multimerization of KIF1A. In addition, point mutations causing rigidity in the predicted flexible hinge disrupt the intramolecular FHA-CC2 interaction and increase MT binding and peripheral accumulation of KIF1A. These results suggest that the intramolecular FHA-CC2 interaction negatively regulates KIF1A activity by inhibiting MT binding and dimerization of KIF1A, and point to a novel role of the FHA domain in the regulation of kinesin motors.