Tip-end fusion of a rod-shaped secretory organelle.

ABSTRACT: Weibel-Palade bodies (WPB) are elongated, rod-like secretory organelles unique to endothelial cells that store the pro-coagulant von-Willebrand factor (VWF) and undergo regulated exocytosis upon stimulation with Ca²⁺- or cAMP-raising agonists. We show here that WPB preferentially initiate fusion with the plasma membrane at their tips and identify synaptotagmin-like protein 2-a (Slp2-a) as a positive regulator of VWF secretion most likely mediating this topological selectivity. Following secretagogue stimulation, Slp2-a accumulates at one WPB tip before fusion occurs at this site. Depletion of Slp2-a reduces Ca²⁺-dependent secretion of highly multimeric VWF and interferes with the formation of actin rings at WPB-plasma membrane fusion sites that support the expulsion o

SUBMITTER: Naß J 

PROVIDER: S-EPMC9167223 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature