OSBP-Related Protein Family in Lipid Transport Over Membrane Contact Sites.
OSBP-Related Protein Family in Lipid Transport Over Membrane Contact Sites.
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DOI：
10.4137/lpi.s31726
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Olkkonen VM
中科院分区：
文献类型：
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作者：
Olkkonen VM
越来越多的证据表明，氧固醇结合蛋白相关蛋白（ORP）定位于膜接触位点，这是小分子和信息的细胞器间交换的高容量平台。氧化还原酶可以同时与两个并列的膜和转移脂质跨双分子层间隙。氧固醇结合蛋白通过磷脂酰肌醇-4-磷酸（PI 4P）的逆行转运将胆固醇从内质网转移到高尔基体。类似地，酵母Osh 6p介导磷脂酰丝氨酸从内质网转运到质膜以交换PI 4P，并且ORP 5和-8被认为在哺乳动物细胞中执行类似的功能。ORP可能在其配体结合结构域中具有结合PI 4P的能力，这促使人们假设磷酸肌醇和另一种脂质的双向转运可能是蛋白质家族中的共同主题。然而，该模型需要更多的实验支持，并且不排除ORP在脂质信号传导中的功能。
Increasing evidence suggests that oxysterol-binding protein-related proteins (ORPs) localize at membrane contact sites, which are high-capacity platforms for inter-organelle exchange of small molecules and information. ORPs can simultaneously associate with the two apposed membranes and transfer lipids across the interbilayer gap. Oxysterol-binding protein moves cholesterol from the endoplasmic reticulum to trans-Golgi, driven by the retrograde transport of phosphatidylinositol-4-phosphate (PI4P). Analogously, yeast Osh6p mediates the transport of phosphatidylserine from the endoplasmic reticulum to the plasma membrane in exchange for PI4P, and ORP5 and -8 are suggested to execute similar functions in mammalian cells. ORPs may share the capacity to bind PI4P within their ligand-binding domain, prompting the hypothesis that bidirectional transport of a phosphoinositide and another lipid may be a common theme among the protein family. This model, however, needs more experimental support and does not exclude a function of ORPs in lipid signaling.