Heme is a vital but cytotoxic cofactor responsible for diverse biological functions. Free heme is a hydrophobic and cytotoxic macrocycle. How then is heme transported through cellular membranes and organelles? We pioneered the use of C. elegans to discover heme trafficking pathways because this roundworm is exceptional as it does not synthesize heme but rather utilizes environmental heme to manufacture heme-containing proteins which have human homologs. In the last few years, we have uncovered several new molecules that traffic and regulate systemic heme homeostasis using genetic screens in C. elegans. Our findings represent major discoveries in heme trafficking and establish a paradigm for heme transport in animals.
