Algae Yields Link to Human Health
Labels marking bags of donated blood throughout the world contain information about the presence of a Rhesus (Rh) antigen, a protein found on the membranes of human red blood cells. Yet, despite the Rh protein's importance in blood transfusion and the problems it can cause between Rh negative mothers and their Rh positive fetuses, its biological role has remained largely unresolved since its discovery 65 years ago.
But a new study, led by Sydney Kustu, professor of plant and microbial biology, may help clarify the mystery by giving additional evidence that the Rh protein serves as a gas channel for carbon dioxide (CO2). Kustu recently received the Miller Research Professorship Award, an honor that comes with one year of research free from other obligations—time she will use to continue her work on gas channels and to expand her familiarity with their role in human physiology.
"This finding has implications for understanding how humans breathe, how we control the acidity of various fluids in our bodies, and how our kidneys function, all of which rely upon movement of CO2 across cell membranes," says Kustu.
The researchers came to their conclusions by studying a humble green alga, Chlamydomonas reinhardtii, one of the few microorganisms known to have Rh.
What do Rh proteins in green algae have to do with Rh proteins in humans? "It turns out that if you know the biochemical function of a protein, you know it," said Kustu. "A protein's biochemical function does not change from organism to organism."
The Rh protein's role in CO2 transport makes sense given its location on the surface of red blood cells. "Red blood cells need to transport CO2 from body tissue out through the capillaries of the lungs very quickly, and the Rh protein in blood cells is about speed," says Kustu.
In addition to being present in red blood cells, Rh proteins are found in a variety of human organs including seminal vesicles and the kidney and brain. "Their location points to the multiple roles Rh proteins play in human physiology," said Kustu. "All this is to say that there is more to Rh proteins than previously thought, and they deserve more research. Studying them will lead in many interesting directions."