Chi-Min Ho, Ph.D.
Assistant Professor of Microbiology & Immunology
Ph.D., University of California, Los Angeles
Host-pathogen interactions, membrane protein complexes, malaria, cyro electron microscopy and tomography
Our lab is in interested in understanding how membrane protein complexes mediate host-pathogen interactions in endogenous malaria parasites, using biochemistry and the latest advances in single-particle cryo electron microscopy and cryoFIB-enabled in situ cryo electron tomography.
The complexity and breadth of its host-cell remodeling machinery make P. falciparum a rich and exciting system for the study of host-pathogen interfaces. However, many of the molecular mechanisms underlying this parasite’s ability to hijack human red blood cells remain enigmatic, as much of the P. falciparum proteome has proven recalcitrant to structural and biochemical characterization using traditional recombinant approaches. Our lab uses single-particle cryo electron microscopy to determine near-atomic resolution structures of previously intractable protein complexes enriched directly from endogenous P. falciparum parasites, and cryoFIB-enabled in situ cryo electron tomography to directly visualize the host-pathogen interface in parasite-infected red blood cells at sub-nanometer resolutions.
While most intracellular pathogens export a limited repertoire of effector proteins to co-opt existing host-cell metabolic machineries, the malaria-causing parasite Plasmodium falciparum exports more than 10% of its proteome into its host, the human red blood cell, which the parasite inhabits and reproduces within during the blood stages of its life cycle. The hundreds of proteins in the P. falciparum exportome extensively remodel host erythrocytes, creating the infrastructure needed to import nutrients, export waste, and evade the host immune system. The export of these hundreds of proteins is complicated by the fact that the malaria parasite conceals itself inside a parasitophorous vacuole (PV) derived from invagination of the host cell plasma membrane during invasion. Following secretion into the PV, proteins destined for export must be unfolded and transported across the PV membrane (PVM) into the host cell in an ATP-dependent process.
To learn more, visit our lab website.
Ho, C.M.*, Li, X.*, Lai, M, Terwilliger, T.C., Beck, J.R., Wohlschegel, J.A., Goldberg, D.E., Fitzpatrick, A.W.P. and Zhou, Z.H. (2019) Bottom-up structural proteomics: cryoEM of protein complexes enriched from the cellular milieu. Nature Methods, accepted.
Ho, C.M., Beck, J.R., Lai, M., Cui, Y., Goldberg, D.E., Egea, P.F. and Zhou, Z.H. (2018) Malaria parasite translocon structure and mechanism of effector export. Nature 561: 70-75.
Gruswitz, F., Chaudhary, S., Ho, J.D., Schlessinger, A., Pezeshki, B., Ho, C.M., Sali, A., Westhoff, C.M. and Stroud, R.M. (2010) Function of human Rh based on structure of RhCG at 2.1 Å. Proc. Natl. Acad. Sci. U.S.A. 107: 9638-9643.
Li, M., Hays, F.A., Roe-Zurz, Z., Vuong, L., Kelly, L., Ho, C.M., Robbins, R.M., Pieper, U., O’Connell, J.D., Miercke, L.J.W., Giacomini, K.M., Sali, A. and Stroud, R.M. (2009) Selecting optimum eukaryotic integral membrane proteins for structure determination by rapid expression and solubilization screening. J. Mol. Biol. 385: 820-830.