Shaul P W, Anderson R G
Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75235-9063, USA.
Am J Physiol. 1998 Nov;275(5):L843-51. doi: 10.1152/ajplung.1998.275.5.L843.
Caveolae are specialized plasmalemmal microdomains originally studied in numerous cell types for their involvement in the transcytosis of macromolecules. They are enriched in glycosphingolipids, cholesterol, sphingomyelin, and lipid-anchored membrane proteins, and they are characterized by a light buoyant density and resistance to solubilization by Triton X-100 at 4 degreesC. Once the identification of the marker protein caveolin made it possible to purify this specialized membrane domain, it was discovered that caveolae also contain a variety of signal transduction molecules. This includes G protein-coupled receptors, G proteins and adenylyl cyclase, molecules involved in the regulation of intracellular calcium homeostasis, and their effectors including the endothelial isoform of nitric oxide synthase, multiple components of the tyrosine kinase-mitogen-activated protein kinase pathway, and numerous lipid signaling molecules. More recent work has indicated that caveolae further serve to compartmentalize, modulate, and integrate signaling events at the cell surface. This specialized plasmalemmal domain warrants direct consideration in future investigations of both normal and pathological signal transduction in pulmonary cell types.
小窝是一种特殊的质膜微区，最初在多种细胞类型中进行研究，因其参与大分子的转胞吞作用。它们富含糖鞘脂、胆固醇、鞘磷脂和脂锚定膜蛋白，其特征是具有轻的浮力密度且在4℃下对Triton X - 100的溶解具有抗性。一旦标记蛋白小窝蛋白的鉴定使得纯化这种特殊的膜结构域成为可能，就发现小窝还包含多种信号转导分子。这包括G蛋白偶联受体、G蛋白和腺苷酸环化酶、参与细胞内钙稳态调节的分子，以及它们的效应器，包括一氧化氮合酶的内皮异构体、酪氨酸激酶 - 丝裂原活化蛋白激酶途径的多个组分，以及众多脂质信号分子。最近的研究表明，小窝进一步起到在细胞表面分隔、调节和整合信号事件的作用。在未来对肺细胞类型正常和病理信号转导的研究中，这种特殊的质膜结构域值得直接关注。
