Current Lab Members
Dr. Michael S. Marks
Professor of Pathology and Laboratory Medicine • Duke University (Ph.D.) • Cornell University (B.S.)
marksm@pennmedicine.upenn.edu
Publications
My lab focuses on molecular mechanisms controlling membrane trafficking and morphogenesis during the formation of lysosome-related organelles in several cell types, and how these mechanisms are disrupted in disease. We have largely focused particularly on the biogenesis of melanosomes – lysosome-related organelles in which melanin is synthesized and stored in skin melanocytes and in choroid melanocytes, retinal pigment epithelia, and iris pigment epithelia in the eye. Defects in melanosome biogenesis result in ocular or oculocutaneous albinism either in isolation (non-syndromic albinism) or as part of a broader disease of lysosome-related organelle biogenesis (syndromic albinism, e.g. the Hermansky-Pudlak syndromes). We have also worked with collaborators to extend our findings on melanosomes into other systems, including the formation of dense granules in platelets (required for optimal blood clotting), the formation of lamellar bodies in lung epithelial cells (required for surfactant secretion in the lung), and the maturation of phagosomes in dendritic cells (required for innate immunity and antigen presentation in the immune system). These systems are related through their disruption in rare diseases of membrane trafficking components such as the Hermansky-Pudlak syndromes. More recently, we have collaborated with others to investigate the mechanisms by which genes that control natural pigment variation in human populations function in melanocytes. This has led us to investigate other rare diseases, including ciliopathies such as Joubert syndrome and Bardet-Biedl syndrome.
Dawn Harper
Research Associate • University of Pennsylvania (M.S.) • West Chester University of Pennsylvania (B.S.)
sabine1913@gmail.com
Publications
My work is focused on understanding how specific proteins and protein complexes are assembled and sorted to the appropriate compartments within the late secretory and endocytic pathways, and how sorting and assembly contributes to the biogenesis of lysosome-related organelles (LROs) and the diseases resulting from malformation of LROs in specialized cells.
Roseanne Davila-Rivera
BBCB Graduate Group PhD Candidate (Biochemistry, Biophysics, & Chemical Biology program) • Universidad de Puerto Rico (B.S., 2014)
rdavilar@pennmedicine.upenn.edu
Publications
My research project focuses on the biochemical characterization of BLOC-2 in melanosome maturation. BLOC-2 is a protein complex composed of three large subunits—HPS3, HPS5, and HPS6—that is required to direct tubular transport carriers to melanosome membranes. Through this pathway, key proteins necessary for melanosome maturation are delivered. My ongoing efforts are aimed at elucidating the three-dimensional structure of BLOC-2 by cryo-EM and identifying its interacting partners to better understand its role in this pathway.
In my free time, I enjoy exploring new places, traveling, painting, dancing, and trying different types of food—from food trucks to fancy restaurants. There are no limits (I’m a foodie!).
Dr. Brice Magne
Postdoctoral Researcher • Université Paris-Saclay, Orsay, FR (Ph.D., 2019) • Cranfield University, Bedford, UK (M.S., 2016) • Université de Technologie de Compiègne, Compiègne, FR (Ing., 2015)
magneb@chop.edu
Publications
I am currently exploring the role of the primary cilium, and more specifically TMEM138, in melanogenesis and pigmentation, using various approaches including fixed cell imaging, qPCR, flow cytometry, melanin content assays, Western blots, and reconstructed skin. My aim is to reach a faculty position to explore the mechanisms regulating the biogenesis of cutaneous LROs, including Odland bodies and melanosomes.
In addition to spending too much time in the lab, I enjoy going out, baking, cooking, making cocktails (and drinking them), cuddling with my cat, and playing board games and video games. My favorite book is Froth on the Daydream by Boris Vian, and I love a good drag show!
Rachel Welles
CAMB Graduate Group Ph.D. Candidate (Cell Biology, Physiology, and Metabolism program) • Haverford College (B.S., 2021)
rachel.welles@pennmedicine.upenn.edu
Publications
My work explores the function of BLOC-2 in melanosome motility and biogenesis primarily through live-cell microscopy and particle tracking. BLOC-2 is crucial in facilitating contacts between early endosome tubules and maturing melanosomes to deliver melanogenic cargoes, but the mechanism is unknown. I hypothesize that BLOC-2 is interacting with molecular motors to help "find" the ends of these cargo-carrying tubules and will investigate this during my Ph.D. research.
When I'm not in lab, I love to read, play video games, and explore new restaurants and museums in the city!