May accelerate cholesterol efflux from endothelial cells to high-density lipoprotein (HDL) and thereby regulates angiogenesis. May orchestrate hematopoietic stem and progenitor cell emergence from the hemogenic endothelium, a type of specialized endothelium manifesting hematopoietic potential. YJEFN3-mediated cholesterol efflux activates endothelial SREBF2, the master transcription factor for cholesterol biosynthesis, which in turn transactivates NOTCH and promotes hematopoietic stem and progenitor cell emergence (By similarity). May play a role in spermiogenesis and oogenesis (By similarity). Interacts with APOA1 (By similarity). Binds to HDL (By similarity).