Cellular Function of a Protein, NMB, Important in Eye Disease

Alexander C Theos, PhD
Georgetown University, School of Nursing &Health Studies (Washington, DC, United States)
Year Awarded:
Grant Duration:
July 1, 2012 to August 31, 2014
Award Amount:
Grant Reference ID:
Award Type:
Award Region:
US Southeastern
Alexander C Theos, PhD

Cell Biology of NMB in Pigmentary Glaucoma


DBA/2J mice are an animal model of pigment dispersion syndrome (PDS), which is a precursor to glaucoma in humans. These mice are thought to have a loss-of-function mutation in the NMB gene that is responsible for this disease. Dr. Theos and colleagues are proposing experiments that will characterize the NMB protein within pigmented cells of the eye in order to understand how NMB functions in normal cells, and, in addition, how loss of function of NMB causes PDS.


Dr. Theos and colleagues will look at the cells in the eye that produce the pigment that gives the iris its color. These cells die as a prelude to the development of a type of inherited glaucoma known as pigmentary glaucoma (PG). Unfortunately, very little is known about why these particular cells within the eye do not survive with age and cause problems that lead to the disease. These researchers will use cells from the eyes of DBA/2J mice that develop PDS to test if a specific protein, called NMB, is important for keeping the cells healthy by making and storing these pigments within the confines of a specialized cell compartment. To get a handle on this, the researchers will first determine if the normal protein is in the right place within cells to carry out this type of function.

The results of this research may have an impact on other devastating diseases, as NMB has recently been shown to be critically important not only in PG, but also in a rare but devastating cancer of the eye called uveal melanoma. If Theos and colleagues can fully understand how NMB leads to changes in the behavior of eye cells, this will help to develop new therapies to correct the problem or even prevent the development of these debilitating diseases.

About the Researcher

Dr. Alexander Theos is an Assistant Professor in the Department of Human Science at Georgetown University Medical Center, Washington, DC. He completed his doctoral studies at Cambridge University, United Kingdom, in Clinical Biochemistry under the mentorship of Dr. Margaret (Scottie) Robinson. After completing a Postdoctoral Fellowship at the University of Pennsylvania, Philadelphia, PA, he was a Visiting Professor of Biology at Swarthmore College, Swarthmore, PA, before moving to Georgetown. Theos's cell biology laboratory seeks to answer questions related to the biogenesis of lysosome-related organelles in specialized tissues. To this end, his lab focuses on the very basic molecular events by which soluble and membrane-associated proteins are transported to melanosomes, the pigment granules of mammalian cells. The aberrant functioning of machinery and cargo involved in this fascinating process often leads to human disease.
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