Fig. 8. Schematic representation of FLVCR1a function in endothelial cells.

Graphic representation of wild-type a and FLVCR1a null b endothelial cells. FLVCR1a exports the excess of heme derived from heme biosynthesis, thus contributing to maintain heme homeostasis. The loss of FLVCR1a leads to cytosolic heme accumulation and triggers paraptotic cell death characterized by extensive cytoplasmic vacuolation, swollen morphology of endoplasmic reticulum and large mitochondria without cristae. The effects of FLVCR1a loss in ECs in vivo cause deficient angiogenesis, hemorrhages and embryonic lethality. M mitochondrion; ER endoplasmic reticulum; V vacuoles; N nucleus