• Affiliate Professor, Global Health
Marilyn Parsons

Center for Infectious Disease Research
307 Westlake Ave N, Suite 500
Seattle, WA 98109
United States

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Among different disease agents, parasites are the most similar to their human hosts. This has made the search for drugs and vaccines highly challenging. Scientists in Dr. Parsons' laboratory are interested in identifying differences in cell structure and function between parasites and humans.

The lab studies several parasites including Trypanosoma brucei (African trypanosomes), Leishmania, and Toxoplasma gondii. These pathogens are the causative agents of African sleeping sickness, leishmaniasis, and toxoplasmosis, respectively. Up to 300,000 individuals are estimated to be infected with African trypanosomes. Left untreated, sleeping sickness is invariably fatal.

The World Health Organization estimates that 12 million people are infected with Leishmania parasites, although some show no signs of disease. Co-infection with HIV however, leads to severe, often fatal, leishmaniasis. T. gondii infects approximately 50 million Americans, and causes disease in the immunocompromised. It also is a significant cause of birth defects if the mother becomes infected early in pregnancy.

Dr. Parsons' interest in these parasites stems from both an interest in their role as important pathogens worldwide and in their basic biology as evolutionarily divergent eukaryotes. Her long-term goal is to identify differences between host and parasite that would be appropriate targets for drug development.

Currently, Dr. Parsons' two focal areas of research are protein phosphorylation and organelle biogenesis and function in parasitic protozoa. Her lab uses technologies ranging from fluorescence microscopy to molecular genetics to study the functional attributes of these processes. In Toxoplasma, the lab examines the biogenesis of the apicoplast, an essential, relict chloroplast also found in malaria parasites. In T. brucei, studies explore the roles of protein kinases, which in other organisms control critical cellular and developmental processes. The lab is particularly interested in kinases since drugs can successfully be developed against this class of enzymes. A second project in T. brucei examines the role of the mitochondrion in the form of the parasite that infects the mammalian host.

  • PhD (Stanford University)
  • BA (University of Kansas)
Country Affiliations 
Health Topics 
  • Infectious Diseases
  • Pathobiology
  • Zoonotic Diseases and Animal Health
Pathobiology research areas 

Molecular and cellular parasitology


A thioredoxin family protein of the apicoplast periphery identifies abundant candidate transport vesicles in Toxoplasma. Derocher AE, Coppens I, Karnataki A, Gilbert LA, Rome ME, Feagin JE, Bradley PJ, Parsons M.
Eukaryot Cell. 2008 Jun 27. [Epub ahead of print]

A membrane protease is targeted to the relict plastid of toxoplasma via an internal signal sequence. Karnataki A, Derocher AE, Coppens I, Feagin JE, Parsons M.
Traffic. 2007 Nov;8(11):1543-53. Epub 2007 Sep 6.

Conservation of PEX19-binding motifs required for protein targeting to mammalian peroxisomal and trypanosome glycosomal membranes. Saveria T, Halbach A, Erdmann R, Volkmer-Engert R, Landgraf C, Rottensteiner H, Parsons M.
Eukaryot Cell. 2007 Aug;6(8):1439-49. Epub 2007 Jun 22.

Kayode K. Ojo, K.K., Larson, E.T., Keyloun, K.R., Castaneda, L.J., DeRocher, A.E., Inampudi, K.K., Kim, J.E., Tracy L. Arakaki, T.L., Murphy, R., Zhang, L., Napuli, A.J., Maly, D.J., Verlinde, C.M., Buckner, F.S., Parsons, M., Hol, W.J.G., Merritt, E.A., and Van Voorhis, W.C. (2010) A Unique variation of the ATP binding site makes Toxoplasma gondii calcium-dependent protein kinase 1 a drug target for selective kinase inhibitors. Nat. Struct. Mol. Biol., 17: 602-507. PMCID: PMC2896873.

Flaspohler, J.A., Jensen, B.C., Saveria, T., Kifer, C.T., and Parsons, M. (2010) A novel protein kinase localized to lipid droplets is required for droplet biogenesis in trypanosomes. Eukaryotic Cell, 9: 17-2-1710. PMCID: PMC2976304.

Surve, S., Heestand, M., Panicucci, B., Schnaufer, A., and Parsons, M. (2012). Enigmatic presence of mitochondrial complex I in Trypanosoma brucei bloodstream forms. Eukaryotic Cell, 11:183-193. (Spotlight article). PMCID: PMC3272898.

DeRocher, A.E., Karnataki, A., Vaney, P., and Parsons, M. (2012). Apicoplast targeting of a T. gondii transmembrane protein requires a cytosolic tyrosine-based motif. Traffic, 123: 694-704. PMCID: PMC3324616.

Kalidas, S., Cestari, I., Monnerat, S., Li, Q., Regmi, S., Hasle, N., Labaied, M., Parsons, M., Stuart, K., Phillips, M.A. (2014) Genetic validation of aminoacyl-tRNA synthetases as drug targets in Trypanosoma brucei. Eukaryot Cell. 13:504-16. PMCID: PMC4000095.

Jensen, B.C., Ramasamy, G., Vasconcelos, E.J.R., Ingolia, N.T., Myler, P.J., and Parsons, M. (2014) Extensive stage-regulation of translation revealed by ribosome profiling of Trypanosoma brucei. BMC Genomics 15:911.