Maekawa Masashi, Yang Yanbo, Fairn Gregory D
Keenan Research Centre for Biomedical Science, St. Michael's Hospital, 209 Victoria Street, 6th Floor, Toronto, ON M5S 1T8, Canada.
Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada.
Toxins (Basel). 2016 Mar 8;8(3):67. doi: 10.3390/toxins8030067.
Cholesterol is an essential structural component of cellular membranes in eukaryotes. Cholesterol in the exofacial leaflet of the plasma membrane is thought to form membrane nanodomains with sphingolipids and specific proteins. Additionally, cholesterol is found in the intracellular membranes of endosomes and has crucial functions in membrane trafficking. Furthermore, cellular cholesterol homeostasis and regulation of de novo synthesis rely on transport via both vesicular and non-vesicular pathways. Thus, the ability to visualize and detect intracellular cholesterol, especially in the plasma membrane, is critical to understanding the complex biology associated with cholesterol and the nanodomains. Perfringolysin O (PFO) theta toxin is one of the toxins secreted by the anaerobic bacteria Clostridium perfringens and this toxin forms pores in the plasma membrane that causes cell lysis. It is well understood that PFO recognizes and binds to cholesterol in the exofacial leaflets of the plasma membrane, and domain 4 of PFO (D4) is sufficient for the binding of cholesterol. Recent studies have taken advantage of this high-affinity cholesterol-binding domain to create a variety of cholesterol biosensors by using a non-toxic PFO or the D4 in isolation. This review highlights the characteristics and usefulness of, and the principal findings related to, these PFO-derived cholesterol biosensors.
胆固醇是真核生物细胞膜的重要结构成分。质膜外小叶中的胆固醇被认为与鞘脂和特定蛋白质形成膜纳米结构域。此外，胆固醇存在于内体的细胞内膜中，在膜运输中具有关键作用。此外，细胞胆固醇稳态和从头合成的调节依赖于通过囊泡和非囊泡途径的运输。因此，可视化和检测细胞内胆固醇的能力，尤其是质膜中的胆固醇，对于理解与胆固醇和纳米结构域相关的复杂生物学至关重要。产气荚膜梭菌θ毒素是厌氧菌产气荚膜梭菌分泌的毒素之一，该毒素在质膜上形成孔导致细胞裂解。众所周知，产气荚膜梭菌θ毒素识别并结合质膜外小叶中的胆固醇，且产气荚膜梭菌θ毒素的结构域4（D4）足以结合胆固醇。最近的研究利用这种高亲和力的胆固醇结合结构域，通过单独使用无毒的产气荚膜梭菌θ毒素或D4创建了多种胆固醇生物传感器。本综述重点介绍了这些源自产气荚膜梭菌θ毒素的胆固醇生物传感器的特性、用途以及主要研究结果。
