Updated project metadata. A Rab27a targeted APEX2 construct was transfected into primary human umbilical endothelial cells (HUVEC) and the proximal proteins surrounding endothelial storage organelles (Weibel Palade bodies) identified by proximity proteomics in unstimulated and stimulated conditions. The procedure was carried out in the presence and absence of two different stimuli (10 minutes-phorbol myristate acetate or a combination of Histamine, adrenalin and 3-isobutyl-1-methylxanthine) and the data presented represents 4 independent experiments each with 2 technical replicates.