ENTH domain proteins are cargo adaptors for multiple SNARE proteins at the TGN endosome
ENTH domain proteins are cargo adaptors for multiple SNARE proteins at the TGN endosome
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DOI：
10.1242/jcs.012708
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发表时间：
2008-02-01
影响因子：
4
通讯作者：
von Mollard, Gabriele Fischer
中科院分区：
文献类型：
--
作者：
Chidambaram, Subbulakshmi;Zimmermann, Jana;von Mollard, Gabriele Fischer
ENTH 和 ANTH 结构域蛋白参与网格蛋白包被囊泡的出芽。 SNARE 是融合蛋白，在运输囊泡的靶向和融合中发挥作用。在哺乳动物和酵母细胞中，ENTH 结构域蛋白（epsinR 和 Ent3p）与 vti1 家族（Vti1b 或 Vti1p）的 SNARE 相互作用。这种相互作用表明 ENTH 蛋白可以在货物分选中发挥作用，这促使我们寻找其他 SNARE 作为 Ent3p 和 epsinR 的潜在货物。我们进行了特定的酵母双杂交测定，鉴定了 epsinR 与哺乳动物晚期内体 SNARE 突触蛋白 7 和突触蛋白 8 之间以及 Ent3p 与来自酵母的内体 SNARE Pep12p 和 Syn8p 之间的相互作用。 Ent3p 的缺乏影响了 Pep12p 的贩运。 Ent3p 与 Pep12p 的结合需要 Pep12p 中的 FSD 晚期内体分选信号。分选信号的失活与去除 Ent3p 对 Pep12p 稳定性的影响相似，表明 Ent3p 通过与分选信号结合而充当 Pep12p 的货物适配器。由于 Vti1p、Pep12p 和 Syn8p 参与 SNARE 复合体，而 Vti1b、突触蛋白 7 和突触蛋白 8 是哺乳动物 SNARE 伙伴，因此我们提出 TGN 内体的 ENTH 结构域蛋白是这些内体 SNARE 的货物适配器。
ENTH and ANTH domain proteins are involved in budding of clathrin-coated vesicles. SNAREs are fusogenic proteins that function in the targeting and fusion of transport vesicles. In mammalian and yeast cells, ENTH domain proteins ( epsinR and Ent3p) interact with SNAREs of the vti1 family ( Vti1b or Vti1p). This interaction indicates that ENTH proteins could function in cargo sorting, which prompted us to search for additional SNAREs as potential cargo for Ent3p and epsinR. We carried out specific yeast two-hybrid assays, which identified interactions between epsinR and the mammalian late endosomal SNAREs syntaxin 7 and syntaxin 8 as well as between Ent3p and the endosomal SNAREs Pep12p and Syn8p from yeast. Lack of Ent3p affected the trafficking of Pep12p. Ent3p binding to Pep12p required the FSD late endosomal sorting signal in Pep12p. Inactivation of the sorting signal had a similar effect to removal of Ent3p on Pep12p stability indicating that Ent3p acts as a cargo adaptor for Pep12p by binding to the sorting signal. As Vti1p, Pep12p and Syn8p participate in a SNARE complex whereas Vti1b, syntaxin 7 and syntaxin 8 are mammalian SNARE partners, we propose that ENTH domain proteins at the TGN-endosome are cargo adaptors for these endosomal SNAREs.