Slipping out the Weibel-Palade body

摘要

Weibel-Palade bodies (WPBs) are versatile storage organelles within endothe-lial cells that release their inflammatory and prothrombotic content into the circulation in response to a large number of agonists. Using real-time analysis of fluorescently tagged von Willebrand factor (VWF) and VWF propolypeptide, Babich et al nicely show that a proportion of WPBs transiently fuse with the plasma membrane during a "lingering kiss."Fusion pores of approximately 12 nm in diameter are generated that facilitate the selective release of low-molecular-weight components like IL-8 from these organelles. An important physiological implication of these findings is that endothelial cells can selectively release proinflammatory cytokines like IL-8 and eotaxin-3 while retaining prothrombotic VWF. The selective release of small-core and membrane proteins comes at a cost, though;#