Biologists have uncovered the little known mechanism of transport of haem, biologically significant compounds crucial to various bodily functions, in worms1. The finding may provide important insights into human disorders of haem metabolism and help find new drug targets to treat worm infestations.
Haem plays an important role in many functions such as respiration, gas sensing, xenobiotic detoxification, cell differentiation, circadian clock control, metabolic reprogramming and microRNA processing. Haem is generally synthesized by a multistep biosynthetic pathway comprising defined intermediates. Much was known about how haem is synthesised and degraded, but how it travels from one cell to another was relatively unknown.
A collaboration of Indo-American scientists studied haem trafficking in helminthe called Caenorhabditis elegans, which have the ability to acquire haem from the environment. They identified previously unknown HRG-1 and HRG-4 transmembrane proteins essential for haem homeostasis and normal development in worms and vertebrates.
Since human and worm proteins localize together, and bind and transport haem, they have an evolutionarily conserved function for HRG-1. The new findings show conserved pathways for cellular haem trafficking in animals that define the model for eukaryotic haem transport.
