The plant ESCRT component FREE1 regulates peroxisome-mediated turnover of lipid droplets in germinating Arabidopsis seedlings
The plant ESCRT component FREE1 regulates peroxisome-mediated turnover of lipid droplets in germinating Arabidopsis seedlings
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植物 ESCRT 成分 FREE1 调节发芽拟南芥幼苗中过氧化物酶体介导的脂滴周转
DOI：
10.1093/plcell/koac195
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发表时间：
2022-07-01
期刊：
影响因子：
11.6
通讯作者：
Jiang, Liwen
中科院分区：
文献类型：
--
作者：
Huang, Shuxian;Liu, Zhiqi;Jiang, Liwen
在种子发育期间储存的脂滴（LD）被动员并提供必需的能量和脂质以支持发芽后的幼苗生长。甘油三酯（TAG）是储存在LD中的主要中性脂质。在拟南芥中水解TAG的脂肪酶SUGAR DEPENDENT 1（SDP 1）定位于过氧化物酶体上，并通过过氧化物酶体延伸运输到LD表面，但其潜在机制仍然不清楚。在这里，我们报告了一个以前未知的功能，植物独特的内体分选复合物所需的运输（ESCRT）组件FYVE结构域蛋白质所需的内体分选1（FREE 1）在调节过氧化物酶体/SDP 1介导的LD营业额在拟南芥。我们发现，LD降解受损发芽free 1突变体，此外，在free 1突变体中的SDP 1-或过氧化物酶11 e（PEX 11 e）标记的过氧化物酶体和迁移的SDP 1-阳性过氧化物酶体到LD表面的微管被改变。电子断层扫描分析表明，过氧化物酶体未能形成小管吞噬LD在自由1，不像在野生型。FREE 1与PEX 11 e和SDP 1直接相互作用，表明这些相互作用可能调节过氧化物酶体的延伸和脂肪酶SDP 1向LDs的运输。结果表明，FREE 1通过调节过氧化物酶体微管蛋白和SDP 1靶向作用在萌发幼苗的LD降解中发挥关键作用，植物特有的ESCRT组分FREE 1通过与PEX 11 e和SDP 1相互作用调节过氧化物酶体微管蛋白和SDP 1靶向作用于脂滴来介导萌发幼苗的LD降解。
Lipid droplets (LDs) stored during seed development are mobilized and provide essential energy and lipids to support seedling growth upon germination. Triacylglycerols (TAGs) are the main neutral lipids stored in LDs. The lipase SUGAR DEPENDENT 1 (SDP1), which hydrolyzes TAGs in Arabidopsis thaliana, is localized on peroxisomes and traffics to the LD surface through peroxisomal extension, but the underlying mechanism remains elusive. Here, we report a previously unknown function of a plant-unique endosomal sorting complex required for transport (ESCRT) component FYVE DOMAIN PROTEIN REQUIRED FOR ENDOSOMAL SORTING 1 (FREE1) in regulating peroxisome/SDP1-mediated LD turnover in Arabidopsis. We showed that LD degradation was impaired in germinating free1 mutant; moreover, the tubulation of SDP1- or PEROXIN 11e (PEX11e)-marked peroxisomes and the migration of SDP1-positive peroxisomes to the LD surface were altered in the free1 mutant. Electron tomography analysis showed that peroxisomes failed to form tubules to engulf LDs in free1, unlike in the wild-type. FREE1 interacted directly with both PEX11e and SDP1, suggesting that these interactions may regulate peroxisomal extension and trafficking of the lipase SDP1 to LDs. Taken together, our results demonstrate a pivotal role for FREE1 in LD degradation in germinating seedlings via regulating peroxisomal tubulation and SDP1 targeting.A plant-unique ESCRT component FREE1 mediates lipid droplet degradation in germinating seedlings by interacting with PEX11e and SDP1 to regulate peroxisomal tubulation and targeting of SDP1 to the lipid droplet.