Uncovering the Ancient Origins of Key Immune Machinery

Our immune cells use chemical attacks to protect us from microscopic invaders. To do this, they rely on cellular machinery called “BLOC” components, which work in a part of the cell called the lysosome-related organelle. This same machinery works in other human cells to send out chemicals that allow blood to clot or pigment that gives hair its colour. Mutations in the BLOC components can lead to a disease called Hermansky Pudlak syndrome, causing symptoms like albinism, visual problems, bleeding disorders, lung scarring, and immune system issues.

Despite their importance, it was unclear where these cellular components came from or the extent to which they exist in other organisms with complex (or “eukaryotic”) cells like ours, like plants, yeasts, algae, or parasites. A new study in the Proceedings of the National Academy of Sciences, published by the lab of Professor Joel Dacks at the University of Alberta and led by Mr. Kiran More and Dr. Paul Manna (a visiting scholar from the University of Gothenburg, Sweden), explored this question. The team used genetic information and evolutionary analyses to show that BLOCs components are widespread across different species, including harmful organisms like the amoeba Acanthamoeba and the plant pathogen Phytophthora, responsible for potato blight.

Collaborating with Dr. Jonathan Kaufman from the University of Cambridge, the researchers also used advanced computational biology techniques (including the recent Nobel prize-winning structural modeling technique) to uncover ancient evolutionary links between the BLOCs and similar cellular machinery which acts in a compartment of our cells called the lysosome, where material is digested. 

These findings suggest that the BLOC machinery plays an important role in microbes today for our ecosystem and health and may help to explain the evolution of the basic cellular configuration over 1.5 billion years ago.