VPS18-regulated vesicle trafficking controls the secretion of pectin and its modifying enzyme during pollen tube growth in Arabidopsis
VPS18-regulated vesicle trafficking controls the secretion of pectin and its modifying enzyme during pollen tube growth in Arabidopsis
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VPS18调节的囊泡运输控制拟南芥花粉管生长过程中果胶及其修饰酶的分泌
DOI：
10.1093/plcell/koab164
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发表时间：
2021-06-14
期刊：
影响因子：
11.6
通讯作者：
Qu, Li-Jia
中科院分区：
文献类型：
--
作者：
Hou, Saiying;Shi, Jiao;Qu, Li-Jia
在真核生物中，同型融合和空泡蛋白分选（HOPS）以及C类核心空泡/内体束缚（CORVET）是进化上保守的膜束缚复合物，其在溶酶体/空泡运输中起重要作用。HOPS和CORVET是否控制着花粉管（生长最快的植物细胞）的内膜运输，在很大程度上仍然是难以捉摸的。在这项研究中，我们证明了四个核心组件共享的两个复合物，拟南芥蛋白分选11（VPS 11），VPS 16，VPS 33，和VPS 18，都是必需的花粉管生长在拟南芥，从而为植物繁殖成功。我们使用VPS 18作为复合物的代表性核心组分，以表明该蛋白质定位于生长中的花粉管中的多泡体（MVBs）和液泡膜。突变体vps 18花粉管在体内生长缓慢，导致雄性传递效率显著降低。进一步的研究表明，从MVB到液泡的膜融合在VPS 18花粉管中严重受损，证实了VPS 18在后期内吞运输中的功能。此外，vps 18花粉管在顶端区产生过量的胞吐小泡，并在细胞壁中产生过量的果胶和果胶甲酯酶。总之，这项研究建立了一个额外的保守作用的HOPS/CORVET在同型膜融合在液泡生物发生在花粉管，并揭示了反馈调节的HOPS/CORVET在分泌细胞壁修饰酶的快速生长的植物细胞。
In eukaryotes, homotypic fusion and vacuolar protein sorting (HOPS) as well as class C core vacuole/endosome tethering (CORVET) are evolutionarily conserved membrane tethering complexes that play important roles in lysosomal/vacuolar trafficking. Whether HOPS and CORVET control endomembrane trafficking in pollen tubes, the fastest growing plant cells, remains largely elusive. In this study, we demonstrate that the four core components shared by the two complexes, Vacuole protein sorting 11 (VPS11), VPS16, VPS33, and VPS18, are all essential for pollen tube growth in Arabidopsis thaliana and thus for plant reproduction success. We used VPS18 as a representative core component of the complexes to show that the protein is localized to both multivesicular bodies (MVBs) and the tonoplast in a growing pollen tube. Mutant vps18 pollen tubes grew more slowly in vivo, resulting in a significant reduction in male transmission efficiency. Additional studies revealed that membrane fusion from MVBs to vacuoles is severely compromised in vps18 pollen tubes, corroborating the function of VPS18 in late endocytic trafficking. Furthermore, vps18 pollen tubes produce excessive exocytic vesicles at the apical zone and excessive amounts of pectin and pectin methylesterases in the cell wall. In conclusion, this study establishes an additional conserved role of HOPS/CORVET in homotypic membrane fusion during vacuole biogenesis in pollen tubes and reveals a feedback regulation of HOPS/CORVET in the secretion of cell wall modification enzymes of rapidly growing plant cells.