Altered Motor Activity of Alternative Splice Variants of the Mammalian Kinesin-3 Protein KIF1B
Altered Motor Activity of Alternative Splice Variants of the Mammalian Kinesin-3 Protein KIF1B
复制标题
DOI：
10.1111/j.1600-0854.2009.00975.x
复制
发表时间：
2009-11-01
期刊：
影响因子：
4.5
通讯作者：
Kanazawa, Hiroshi
中科院分区：
文献类型：
--
作者：
Matsushita, Masafumi;Yamamoto, Ruri;Kanazawa, Hiroshi
几种哺乳动物驱动蛋白马达蛋白作为多个同种型存在，它们由单个基因的选择性剪接产生。然而，许多马达蛋白剪接变体的作用仍不清楚。驱动蛋白-3马达蛋白KIF 1B具有选择性剪接的同种型，其特征在于在蛋白质的保守氨基末端区域中存在或不存在插入序列。插入位于含有富含赖氨酸的簇的环区（也称为K环）和邻近马达结构域的铰链区。为了阐明KIF 1B的这些选择性剪接变体的功能，我们研究了具有和不具有插入序列的重组KIF 1B的生物化学性质。在微管依赖性ATP酶测定中，含有两种插入的KIF 1B变体比不含插入的KIF 1B变体对微管具有更高的活性和亲和力。K环插入的突变分析显示，在该位点具有较长插入序列的变体具有较高的活性。然而，在运动性测定中的运动速度在有和没有插入序列的KIF 1B之间是相似的。我们的研究结果表明，KIF 1B的剪接异构体，在其插入序列不同，有不同的运动活动。
Several mammalian kinesin motor proteins exist as multiple isoforms that arise from alternative splicing of a single gene. However, the roles of many motor protein splice variants remain unclear. The kinesin-3 motor protein KIF1B has alternatively spliced isoforms distinguished by the presence or absence of insertion sequences in the conserved amino-terminal region of the protein. The insertions are located in the loop region containing the lysine-rich cluster, also known as the K-loop, and in the hinge region adjacent to the motor domain. To clarify the functions of these alternative splice variants of KIF1B, we examined the biochemical properties of recombinant KIF1B with and without insertion sequences. In a microtubule-dependent ATPase assay, KIF1B variants that contained both insertions had higher activity and affinity for microtubules than KIF1B variants that contained no insertions. Mutational analysis of the K-loop insertion revealed that variants with a longer insertion sequence at this site had higher activity. However, the velocity of movement in motility assays was similar between KIF1B with and without insertion sequences. Our results indicate that splicing isoforms of KIF1B that vary in their insertion sequences have different motor activities.