Binding of SEC11 Indicates Its Role in SNARE Recycling after Vesicle Fusion and Identifies Two Pathways for Vesicular Traffic to the Plasma Membrane
Binding of SEC11 Indicates Its Role in SNARE Recycling after Vesicle Fusion and Identifies Two Pathways for Vesicular Traffic to the Plasma Membrane
复制标题
DOI：
10.1105/tpc.114.134429
复制
发表时间：
2015-03-01
期刊：
影响因子：
11.6
通讯作者：
Blatt, Michael R.
中科院分区：
文献类型：
--
作者：
Karnik, Rucha;Zhang, Ben;Blatt, Michael R.
SNARE（可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体）蛋白在所有真核生物中驱动囊泡融合，并有助于植物的稳态，病原体防御，细胞扩增和生长。两个同源SNARE，SYP 121（= SYR 1/PEN 1）和SYP 122，占主导地位的分泌交通拟南芥质膜。虽然这些蛋白质在功能上重叠，但SYP 121和SYP 122之间的差异已经浮出水面，这表明它们标志着囊泡运输的两个离散途径。这些SNARE共享主要的同源伙伴，这使得很难将其各自的控制机制分开。在这里，我们表明，调节蛋白SEC 11（=KEULE）选择性地与SYP 121结合，以影响由该SNARE介导的分泌交通。SEC 11拯救交通阻塞的显性负（抑制）片段的两个SNARE，但只有在植物表达的天然SYP 121。交通和救援敏感的突变影响SEC 11与SYP 121的N末端的相互作用。此外，结合SYP 121 N末端的SEC 11结构域本身能够阻断野生型和syp 122中的分泌交通，但在syp 121突变体拟南芥中不能。因此，SEC 11结合并选择性地调节由SYP 121介导的分泌运输，并且对于SNARE及其同源伙伴的再循环是重要的。
SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins drive vesicle fusion in all eukaryotes and contribute to homeostasis, pathogen defense, cell expansion, and growth in plants. Two homologous SNAREs, SYP121 (=SYR1/PEN1) and SYP122, dominate secretory traffic to the Arabidopsis thaliana plasma membrane. Although these proteins overlap functionally, differences between SYP121 and SYP122 have surfaced, suggesting that they mark two discrete pathways for vesicular traffic. The SNAREs share primary cognate partners, which has made separating their respective control mechanisms difficult. Here, we show that the regulatory protein SEC11 (=KEULE) binds selectively with SYP121 to affect secretory traffic mediated by this SNARE. SEC11 rescued traffic block by dominant-negative (inhibitory) fragments of both SNAREs, but only in plants expressing the native SYP121. Traffic and its rescue were sensitive to mutations affecting SEC11 interaction with the N terminus of SYP121. Furthermore, the domain of SEC11 that bound the SYP121 N terminus was itself able to block secretory traffic in the wild type and syp122 but not in syp121 mutant Arabidopsis. Thus, SEC11 binds and selectively regulates secretory traffic mediated by SYP121 and is important for recycling of the SNARE and its cognate partners.