Regulation of microtubule minus-end dynamics by CAMSAPs and Patronin
Regulation of microtubule minus-end dynamics by CAMSAPs and Patronin
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DOI：
10.1073/pnas.1404133111
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发表时间：
2014-04-22
影响因子：
11.1
通讯作者：
Vale, Ronald D.
中科院分区：
文献类型：
--
作者：
Hendershott, Melissa C.;Vale, Ronald D.
微管（MT）细胞骨架在有丝分裂、细胞内运输、细胞形状和细胞迁移中起着重要作用。MT的组装和拆卸，这可以通过在聚合物的正端或负端添加或丢失亚基而发生，对于MT执行其生物学功能是必不可少的。多种蛋白作用于MT末端以调节其动力学，包括最近描述的MT负末端结合蛋白家族，称为钙调蛋白调节的血影蛋白相关蛋白（CAMSAP）/Patronin/Nezha。在果蝇中，Patronin是该家族的唯一成员，以前在体外和体内都显示出稳定MT负末端的解聚作用。在这里，我们表明，所有三个哺乳动物CAMSAP家族成员也特异性地结合到MT负端，并保护他们免受驱动蛋白-13诱导的解聚。然而，这些蛋白质在其抑制微管蛋白在负末端的添加和从MT解离的能力方面不同。CAMSAP 1不干扰聚合，并且沿着沿着生长的负末端跟踪。CAMSAP 2和CAMSAP 3降低微管蛋白掺入的速率并保持结合，从而产生修饰的MT负末端的延伸。通过截断分析，我们发现CAMSAP和Patronin的最小结构域略有不同，参与负端定位。然而，我们发现，在这两种情况下，一个高度保守的C-末端结构域和一个更可变的中央结构域合作，以抑制负末端的动态在体外，这两个地区都需要稳定负末端果蝇S2细胞。这些结果表明，CAMSAP/Patronin家族的成员都本地化，并保护负端，但已经演变出不同的影响MT动态。
The microtubule (MT) cytoskeleton plays an essential role in mitosis, intracellular transport, cell shape, and cell migration. The assembly and disassembly of MTs, which can occur through the addition or loss of subunits at the plus- or minus-ends of the polymer, is essential for MTs to carry out their biological functions. A variety of proteins act on MT ends to regulate their dynamics, including a recently described family of MT minus-end binding proteins called calmodulin-regulated spectrin-associated protein (CAMSAP)/Patronin/Nezha. Patronin, the single member of this family in Drosophila, was previously shown to stabilize MT minus-ends against depolymerization in vitro and in vivo. Here, we show that all three mammalian CAMSAP family members also bind specifically to MT minus-ends and protect them against kinesin-13-induced depolymerization. However, these proteins differ in their abilities to suppress tubulin addition at minus-ends and to dissociate from MTs. CAMSAP1 does not interfere with polymerization and tracks along growing minus-ends. CAMSAP2 and CAMSAP3 decrease the rate of tubulin incorporation and remain bound, thereby creating stretches of decorated MT minus-ends. By using truncation analysis, we find that somewhat different minimal domains of CAMSAP and Patronin are involved in minus-end localization. However, we find that, in both cases, a highly conserved C-terminal domain and a more variable central domain cooperate to suppress minus-end dynamics in vitro and that both regions are required to stabilize minus-ends in Drosophila S2 cells. These results show that members of the CAMSAP/Patronin family all localize to and protect minus-ends but have evolved distinct effects on MT dynamics.