Importin-β Directly Regulates the Motor Activity and Turnover of a Kinesin-4
Importin-β Directly Regulates the Motor Activity and Turnover of a Kinesin-4
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DOI：
10.1016/j.devcel.2018.01.027
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发表时间：
2018-03-12
影响因子：
11.8
通讯作者：
Dixit, Ram
中科院分区：
文献类型：
--
作者：
Ganguly, Anindya;DeMott, Logan;Dixit, Ram
驱动蛋白的时空调节对于微管依赖性细胞内运输至关重要。在植物中，细胞壁沉积取决于FRA 1驱动蛋白，其丰度和运动性受到严格控制以匹配细胞生长速率。在这里，我们表明，一个importin-β，IMB 4，调节FRA 1活性的发展方式。IMB 4与FRA 1运动结构域中的PY基序物理相互作用，并通过阻止微管结合来抑制其运动性，同时还保护FRA 1免受蛋白酶体介导的降解，从而提供了一种将FRA 1的运动性和稳定性偶联的机制。基于植物和动物驱动蛋白马达结构域中PY基序的保守性以及多种植物驱动蛋白与IMB 4的直接相互作用，这种调节机制可能是广泛适用的。总之，我们的数据确立了IMB 4作为FRA 1的多功能调节因子，并揭示了植物如何控制细胞壁组装所需的货物运输量的机制。
Spatiotemporal regulation of kinesins is essential for microtubule-dependent intracellular transport. In plants, cell wall deposition depends on the FRA1 kinesin, whose abundance and motility are tightly controlled to match cellular growth rate. Here, we show that an importin-beta, IMB4, regulates FRA1 activity in a developmental manner. IMB4 physically interacts with a PY motif in the FRA1 motor domain and inhibits its motility by preventing microtubule binding, while also protecting FRA1 against proteasome-mediated degradation, thus providing a mechanism to couple the motility and stability of FRA1. This regulatory mechanism is likely to be broadly applicable, based on the conservation of the PY motif in the motor domains of plant and animal kinesins and the direct interaction of multiple plant kinesins with IMB4. Together, our data establish IMB4 as a multi-functional regulator of FRA1 and reveal a mechanism for how plants control the magnitude of cargo transport needed for cell wall assembly.