Divergent fates of P- and E-selectins after their expression on the plasma membrane.

Abstract

P-selectin and E-selectin are related adhesion receptors for monocytes and neutrophils that are expressed by stimulated endothelial cells. P-selectin is stored in Weibel-Palade bodies, and it reaches the plasma membrane after exocytosis of these granules. E-selectin is not stored, and its synthesis is induced by cytokines. We studied the fate of the two proteins after their surface expression by following the intracellular routing of internalized antibodies to the selectins. By immunofluorescent staining, P-selectin antibody was first seen in endosomes, then in the Golgi region, and finally in Weibel-Palade bodies. In contrast, the E-selectin antibody was detected only in endosomes and lysosomes. Subcellular fractionation of cells after 4 h chase confirmed the localization of P-selectin antibody in storage granules and of the E-selectin antibody in lysosomes. In AtT-20 cells, a mouse pituitary cell line, transfected with P- or E-selectin, only P-selectin was delivered to the endogenous adrenocorticotrophic hormone storage granules after endocytosis. Deletion of the cytoplasmic domain abolished internalization. In summary, after a brief surface exposure, internalized E-selectin is degraded in the lysosomes, whereas P-selectin returns to the storage granules from where it can be reused.

Annexin A8 controls leukocyte recruitment to activated endothelial cells via cell surface delivery of CD63

“…CD63-specific antibodies are internalized and travel through the early and then the late endosomal compartments before eventually reaching the WPB 10 . Likewise, internalized anti-P-selectin antibodies can be found in WPB following transport through endosomes 9 . However, differences appear to exist between the transport of endosomal CD63 and P-selectin to WPB.…”

“…Antibody uptake experiments revealed that plasma membrane CD63 is internalized to late endosomes and a fraction is then transported to WPB. Endothelial activation, in turn, leads to WPB exocytosis and cell surface presentation of CD63, indicating that this tetraspanin cycles between late endosomes and the plasma membrane via WPB 9,10 .…”

A Balance of Opposing Signals within the Cytoplasmic Tail Controls the Lysosomal Targeting of P-selectin

“…Following the stimulation of these cells with thrombin or other agonists, it is redistributed to the plasma membrane (24 -26) and then rapidly internalized (27)(28)(29)(30)(31). When heterologously expressed in cells lacking a regulated secretory pathway, P-selectin is constitutively transported to the cell surface and efficiently endocytosed to lysosomes for degradation (10,28).…”

Re‐expression of functional P‐selectin molecules on the endothelial cell surface by repeated stimulation with thrombin

“…P-selectin disappears from the endothelial cell surface after 60-75 min of stimulation (Hattori et al, 1989a;Sugama et al, 1992) and is believed to be internalized and returned to the Golgi region and Weibel-Palade bodies (Subramaniam et al, 1993;Disdier et al, 1992;Green et al, 1994).…”