SKIP controls lysosome positioning using a composite kinesin-1 heavy and light chain-binding domain.
SKIP controls lysosome positioning using a composite kinesin-1 heavy and light chain-binding domain.
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DOI：
10.1242/jcs.198267
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发表时间：
2017-05-01
影响因子：
4
通讯作者：
Dodding MP
中科院分区：
文献类型：
--
作者：
Sanger A;Yip YY;Randall TS;Pernigo S;Steiner RA;Dodding MP
货物识别和驱动蛋白-1 微管马达活性调节之间的分子相互作用尚不清楚。使用溶酶体适配器 SKIP（也称为 PLEKHM2）作为模型货物，我们表明，除了驱动蛋白轻链（KLC）之外，当存在于扩展的 KHC 相互作用域的背景下时，驱动蛋白重链（KHC）可以识别货物上的色氨酸酸性结合决定簇。 KHC 和 KLC 结合的突变分离表明，这两种相互作用对于体外 SKIP-kinesin-1 相互作用都很重要，而 KHC 结合对于体内溶酶体转运也很重要。然而，在没有 KLC 的情况下，SKIP 仅在自身抑制解除时才能与 KHC 结合，这表明 KLC 控制着 KHC 的通行。我们提出了一个模型，色氨酸酸性货物首先被 KLC 识别，导致 KHC 自抑制不稳定。然后，该主要事件使得可接近 KHC C 末端尾部上邻近自抑制 IAK 区域的第二个 SKIP 结合位点。因此，货物识别和驱动蛋白-1 的并发激活在分子间和分子内相互作用的动态网络驱动下以分层逐步方式进行。摘要：溶酶体驱动蛋白-1 货物适配器 SKIP 通过其重链和轻链与驱动蛋白-1 相互作用。提出了一种新的驱动蛋白-1 激活的逐步分层模型。
The molecular interplay between cargo recognition and regulation of the activity of the kinesin-1 microtubule motor is not well understood. Using the lysosome adaptor SKIP (also known as PLEKHM2) as model cargo, we show that the kinesin heavy chains (KHCs), in addition to the kinesin light chains (KLCs), can recognize tryptophan-acidic-binding determinants on the cargo when presented in the context of an extended KHC-interacting domain. Mutational separation of KHC and KLC binding shows that both interactions are important for SKIP–kinesin-1 interaction in vitro and that KHC binding is important for lysosome transport in vivo. However, in the absence of KLCs, SKIP can only bind to KHC when autoinhibition is relieved, suggesting that the KLCs gate access to the KHCs. We propose a model whereby tryptophan-acidic cargo is first recognized by KLCs, resulting in destabilization of KHC autoinhibition. This primary event then makes accessible a second SKIP-binding site on the KHC C-terminal tail that is adjacent to the autoinhibitory IAK region. Thus, cargo recognition and concurrent activation of kinesin-1 proceed in hierarchical stepwise fashion driven by a dynamic network of inter- and intra-molecular interactions. Summary: The lysosomal kinesin-1 cargo adaptor SKIP is shown to interact with kinesin-1 via both its heavy and light chains. A new stepwise hierarchical model for kinesin-1 activation is proposed.