Is a modulator of endothelial barrier permeability, required for proper organization of endothelial cell-cell junctions and cytoskeleton (PubMed:35638551). It also plays a role in the modulation of secretory autophagy (PubMed:35638551). May affect blood-brain barrier permeability. {ECO:0000269|PubMed:15102925, ECO:0000269|PubMed:35638551}. This is the function of APOLD1 (apolipoprotein L domain containing 1, Ensembl gene identifier ENSG00000178878).