A VPS13D spastic ataxia mutation disrupts the conserved adaptor-binding site in yeast Vps13
A VPS13D spastic ataxia mutation disrupts the conserved adaptor-binding site in yeast Vps13
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DOI：
10.1093/hmg/ddz318
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发表时间：
2020-02-15
影响因子：
3.5
通讯作者：
Conibear, Elizabeth
中科院分区：
文献类型：
--
作者：
Dziurdzik, Samantha K.;Bean, Bjorn D. M.;Conibear, Elizabeth
四种人类VPS 13（VPS 13 A-D）蛋白中的每一种突变都与不同的神经系统疾病相关：舞蹈病-棘红细胞增多症、科恩综合征、早发性帕金森病和痉挛性共济失调。最近的证据表明，不同的VPS 13旁系同源物在不同的膜接触位点的细胞器之间转运脂质。每个VPS 13亚型如何靶向细胞器尚不清楚。我们已经表明，酵母Vps 13蛋白的膜的本地化需要一个保守的六个重复区域，Vps 13衔接子结合（VAB）域，它结合到细胞器特异性衔接子。在这里，我们使用一个系统的诱变策略，以确定每个重复识别每个已知的适配器的作用。我们的研究结果表明，重复序列1和6中的不变天冬酰胺突变强烈影响所有衔接子的结合，并阻断Vps 13膜募集。然而，我们发现重复序列5-6足以定位和与衔接子相互作用。这支持了一种模型，其中在VAB结构域的最后两个重复序列中发现了单个衔接子结合位点，而VAB结构域重复序列1可能影响结构域构象。重要的是，VPS 13 D中的致病突变，其映射到重复序列6中的高度保守的天冬酰胺残基，当在酵母中建模时，阻断接头结合和VPS 13膜募集。我们的研究结果与VAB结构域的保守接头结合作用一致，并表明酵母和人类中存在尚未鉴定的接头。
Mutations in each of the four human VPS13 (VPS13A-D) proteins are associated with distinct neurological disorders: chorea-acanthocytosis, Cohen syndrome, early-onset Parkinson's disease and spastic ataxia. Recent evidence suggests that the different VPS13 paralogs transport lipids between organelles at different membrane contact sites. How each VPS13 isoform is targeted to organelles is not known. We have shown that the localization of yeast Vps13 protein to membranes requires a conserved six-repeat region, the Vps13 Adaptor Binding (VAB) domain, which binds to organelle-specific adaptors. Here, we use a systematic mutagenesis strategy to determine the role of each repeat in recognizing each known adaptor. Our results show that mutation of invariant asparagines in repeats 1 and 6 strongly impacts the binding of all adaptors and blocks Vps13 membrane recruitment. However, we find that repeats 5-6 are sufficient for localization and interaction with adaptors. This supports a model where a single adaptor-binding site is found in the last two repeats of the VAB domain, while VAB domain repeat 1 may influence domain conformation. Importantly, a disease-causing mutation in VPS13D, which maps to the highly conserved asparagine residue in repeat 6, blocks adaptor binding and Vps13 membrane recruitment when modeled in yeast. Our findings are consistent with a conserved adaptor binding role for the VAB domain and suggest the presence of as-yet-unidentified adaptors in both yeast and humans.