PDF(Pubmed)
Abstract：
Cholesterol (Chol) is an essential component of all eukaryotic cell membranes that affects the function of numerous peripheral as well as integral membrane proteins. Chol is synthesized in the ER, but it is selectively enriched within the plasma membrane (PM) and other endomembranes, which requires Chol to cross the aqueous phase of the cytoplasm. In addition to the classical vesicular trafficking pathways that are known to facilitate the bulk transport of membrane intermediates, Chol is also transported via non-vesicular lipid transfer proteins that work primarily within specialized membrane contact sites. Some of these transport pathways work against established concentration gradients and hence require energy. Recent studies highlight the unique role of phosphoinositides (PPIns), and phosphatidylinositol 4-phosphate (PI4P) in particular, for the control of non-vesicular Chol transport. In this chapter, we will review the emerging connection between Chol, PPIns, and lipid transfer proteins that include the important family of oxysterol-binding protein related proteins, or ORPs.
摘要：
胆固醇（Chol）是所有真核细胞膜的重要组成部分，它影响许多外周以及完整的膜蛋白的功能。Chol在ER中合成，但它选择性地富集在质膜（PM）和其他内膜中，这需要Chol穿过细胞质的水相。除了已知有助于膜中间体批量运输的经典囊泡运输途径外，Chol还通过主要在专门的膜接触位点内起作用的非囊泡脂质转移蛋白运输。这些运输途径中的一些对已建立的浓度梯度起作用,因此需要能量。最近的研究强调了磷酸肌醇(PPIns)的独特作用，特别是磷脂酰肌醇4-磷酸酯（PI4P），用于控制非囊泡胆汁转运。在这一章中,我们将回顾Chol之间的新联系，PPIns,和脂质转移蛋白，包括氧固醇结合蛋白相关蛋白的重要家族，或ORP。
