Weibel–Palade body
[1] They manufacture, store and release two principal molecules, von Willebrand factor and P-selectin, and thus play a dual role in hemostasis and inflammation.[4] Storage of long polymers of vWF gives this specialized lysosomal structure an oblong shape and striated appearance on electron microscope.Weibel-Palade bodies undergo a complex maturation process following their dissociation from the trans-Golgi network (TGN) which involves recruitment of a large number of membrane proteins.[9] Some undergo exocytosis individually in a rapid, sub-second fusion event,[17] while others fuse transiently to the plasma membrane in a "lingering kiss" that opens a pore large enough for only their smaller cargo (e.g. IL-8, CD63) to diffuse out.As Weibel–Palade bodies fuse together into secretory pods, their vWF cargo loses its tubular form for spaghetti-like strings that are then exocytosed through a fusion pore.