Predescu Sanda A, Predescu Dan N, Malik Asrar B
Department of Pharmacology and Center for Lung and Vascular Biology, University of Illinois, College of Medicine, Chicago, Illinois 60612, USA.
Am J Physiol Lung Cell Mol Physiol. 2007 Oct;293(4):L823-42. doi: 10.1152/ajplung.00436.2006. Epub 2007 Jul 20.
Caveolae transcytosis with its diverse mechanisms-fluid phase, adsorptive, and receptor-mediated-plays an important role in the continuous exchange of molecules across the endothelium. We will discuss key features of endothelial transcytosis and caveolae that have been studied recently and have increased our understanding of caveolae function in transcytosis at the molecular level. During transcytosis, caveolae "pinch off" from the plasma membrane to form discrete vesicular carriers that shuttle to the opposite front of endothelial cells, fuse with the plasma membrane, and discharge their cargo into the perivascular space. Endothelial transcytosis exhibits distinct properties, the most important being rapid and efficient coupling of endocytosis to exocytosis on opposite plasma membrane. We address herein the membrane fusion-fission reactions that underlie transcytosis. Caveolae move across the endothelial cells with their cargo predominantly in the fluid phase through an active process that bypasses the lysosomes. Endothelial transcytosis is a constitutive process of vesicular transport. Recent studies show that transcytosis can be upregulated in response to pathological stimuli. Transcytosis via caveolae is an important route for the regulation of endothelial barrier function and may participate in different vascular diseases.
小窝转胞吞作用具有多种机制，包括液相、吸附性和受体介导，在分子持续穿过内皮的交换过程中发挥着重要作用。我们将讨论内皮转胞吞作用和小窝的关键特征，这些特征是最近研究的内容，并且在分子水平上增进了我们对小窝在转胞吞作用中功能的理解。在转胞吞过程中，小窝从质膜“掐断”形成离散的囊泡载体，穿梭至内皮细胞的对侧前沿，与质膜融合，并将其货物释放到血管周间隙中。内皮转胞吞作用表现出独特的特性，其中最重要的是在相对质膜上快速且高效地将内吞作用与外排作用偶联起来。我们在此探讨转胞吞作用所基于的膜融合 - 裂变反应。小窝带着其货物主要以液相形式通过一个绕过溶酶体的活跃过程穿过内皮细胞。内皮转胞吞作用是囊泡运输的一个组成性过程。最近的研究表明，转胞吞作用可响应病理刺激而上调。通过小窝的转胞吞作用是调节内皮屏障功能的重要途径，并且可能参与不同的血管疾病。
