AtVPS45 complex formation at the trans-Golgi network
AtVPS45 complex formation at the trans-Golgi network
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DOI：
10.1091/mbc.11.7.2251
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发表时间：
2000-07-01
影响因子：
3.3
通讯作者：
Raikhel, NV
中科院分区：
文献类型：
--
作者：
Bassham, DC;Sanderfoot, AA;Raikhel, NV
Sec1p 蛋白家族被认为通过与目标膜上的 t-SNARE（目标可溶性 N-乙基马来酰亚胺敏感因子附着蛋白受体）相互作用，参与囊泡融合反应的调节。 AtVPS45 是拟南芥这个家族的成员，我们现在证明它存在于跨高尔基体网络 (TGN) 上，与液泡货物受体 AtELP 共定位。与酵母 Vps45p 不同，AtVPS45 不与液泡前 t-SNARE AtPEP12 相互作用或共定位。相反，AtVPS45 与两个 t-SNARE AtTLG2a 和 AtTLG2b 相互作用，这两个 t-SNARE 与酵母 t-SNARE Tlg2p 相似。 AtTLG2a 和 -b 各自与 AtVPS45 在 TGN 共定位；然而，通过免疫金电子显微镜观察，AtTLG2a 与 AtTLG2b 位于 TGN 的不同区域。因此，我们建议包含 AtVPS45 和 AtTLG2a 或 -b 的复合物定义 TGN 的功能子域，并且可能是不同贩运事件所需要的。在其他拟南芥 SNARE 中，AtVPS45 抗体优先共沉淀 AtVTI1b，而不是密切相关的亚型 AtVTI1a，这意味着 AtVTI1a 和 AtVTI1b 在细胞内也具有不同的功能。这些数据表明植物分泌途径内的功能复杂性，其中基因家族编码的蛋白质具有专门的功能，而不是功能冗余。
The Sec1p family of proteins are thought to be involved in the regulation of vesicle fusion reactions through interaction with t-SNAREs (target soluble N-ethylmaleimide-sensitive factor attachment protein receptors) at the target membrane. AtVPS45 is a member of this family from Arabidopsis thaliana that we now demonstrate to be present on the trans-Golgi network (TGN), where it colocalizes with the vacuolar cargo receptor AtELP. Unlike yeast Vps45p, AtVPS45 does not interact with, or colocalize with, the prevacuolar t-SNARE AtPEP12. Instead, AtVPS45 interacts with two t-SNAREs, AtTLG2a and AtTLG2b, that show similarity to the yeast t-SNARE Tlg2p. AtTLG2a and -b each colocalize with AtVPS45 at the TGN; however, AtTLG2a is in a different region of the TGN than AtTLG2b by immunogold electron microscopy. Therefore, we propose that complexes containing AtVPS45 and either AtTLG2a or -b define functional subdomains of the TGN and may be required for different trafficking events. Among other Arabidopsis SNAREs, AtVPS45 antibodies preferentially coprecipitate AtVTI1b over the closely related isoform AtVTI1a, implying that AtVTI1a and AtVTI1b also have distinct functions within the cell. These data point to a functional complexity within the plant secretory pathway, where proteins encoded by gene families have specialized functions, rather than functional redundancy.