Melanophilin and myosin Va track the microtubule plus end on EB1.
Melanophilin and myosin Va track the microtubule plus end on EB1.
复制标题
黑色素和肌球蛋白VA跟踪微管加上EB1上的结尾。
DOI：
10.1083/jcb.200503028
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发表时间：
2005-10-24
影响因子：
7.8
通讯作者：
Hammer, John A 3rd
中科院分区：
文献类型：
--
作者：
Wu, Xufeng S;Tsan, Grace L;Hammer, John A 3rd
在小鼠黑素细胞中，肌球蛋白Va通过受体复合物募集到黑素体表面上，所述受体复合物含有存在于黑素体膜中的Rab 27 a和将肌球蛋白Va连接到Rab 27 a的亲黑素蛋白（Mlp）。在这项研究中，我们表明，Mlp也是一个微管加末端跟踪蛋白或+TIP。此外，肌球蛋白Va以Mlp依赖的方式跟踪正末端。数据显示，+TIP EB 1的过表达和短抑制性RNA敲低对Mlp-微管相互作用具有相反的影响，Mlp直接与EB 1相互作用，并且从Mlp中缺失与参与EB 1结合的腺瘤性结肠息肉病蛋白中的一个区域类似的区域阻断了Mlp的正末端跟踪能力，这表明Mlp通过在EB 1上搭便车直接跟踪正末端。这些结果鉴定了一种新的+TIP，并表明脊椎动物细胞具有类似于酵母中Myo 2 p-Kar 9 p-Bim 1 p复合物的+TIP复合物。我们认为，在这项研究中确定的+TIP复合物可能有助于集中转移的黑素体从微管肌动蛋白在微管加结束。
In mouse melanocytes, myosin Va is recruited onto the surface of melanosomes by a receptor complex containing Rab27a that is present in the melanosome membrane and melanophilin (Mlp), which links myosin Va to Rab27a. In this study, we show that Mlp is also a microtubule plus end–tracking protein or +TIP. Moreover, myosin Va tracks the plus end in a Mlp-dependent manner. Data showing that overexpression and short inhibitory RNA knockdown of the +TIP EB1 have opposite effects on Mlp–microtubule interaction, that Mlp interacts directly with EB1, and that deletion from Mlp of a region similar to one in the adenomatous polyposis coli protein involved in EB1 binding blocks Mlp's ability to plus end track argue that Mlp tracks the plus end directly by hitchhiking on EB1. These results identify a novel +TIP and indicate that vertebrate cells possess a +TIP complex that is similar to the Myo2p–Kar9p–Bim1p complex in yeast. We suggest that the +TIP complex identified in this study may serve to focus the transfer of melanosomes from microtubules to actin at the microtubule plus end.