Siobán Keel, MD
The Keel Laboratory aims to understand normal and abnormal red blood cell development. As a hematology fellow in the Abkowitz Laboratory at the University of Washington, she characterized the erythroid phenotype of mice lacking the heme export protein, Feline Leukemia virus, subgroup C, Receptor (FLVCR). She and others demonstrated that mice lacking FLVCR develop a severe anemia and block in red blood cell maturation. A current focus in the lab is to determine why red blood cell maturation fails in these mice. Heme serves as the functional group of many proteins, including hemoglobin, myoglobin and cytochromes; it also functions as a signaling molecule and is therefore essential for diverse biological processes. However, heme that is not bound to proteins is potentially toxic to cells as it can promote the generation of reactive oxygen species. Thus, heme homeostasis is likely tightly controlled at the level of synthesis, degradation, and use (including export). This research should lend insight into how red blood cells maintain heme balance in the setting of high heme requirements for hemoglobin and the pathologic consequences of perturbing this homeostasis.
A second and new focus of research in the Keel Laboratory is to determine the role of the sodium-phosphate import protein, PiT-1, in hematopoiesis. Phosphate is the second most abundant mineral in the human body and plays an essential role in phospholipids, nucleoproteins and nucleic acids, bone mineralization, the storage and liberation of metabolic energy, and enzyme activities. While our understanding of the mechanisms of phosphate homeostasis has advanced, little is known about how the body initially senses changes in phosphate concentration nor the downstream biological processes regulated by these concentration changes. This work may contribute to the emerging hypothesis that phosphate acts as a signaling molecule which modulates cell proliferation via PiT-1.