Our lab is interested in the molecular events that enable apicomplexan parasites to remain widespread and deadly infectious agents. These single-celled eukaryotes comprise a phylum of organisms that parasitize diverse animal hosts. Many important human pathogens belong to this group, including the causative agents of malaria (Plasmodium spp.), cryptosporidiosis (Cryptosporidium spp.), and toxoplasmosis (Toxoplasma gondii). We use T. gondii to model features conserved throughout the phylum, such as their reliance on calcium signaling to regulate motility. We combine several approaches that span phospho-proteomics, chemical-genetics, and genome editing to investigate the unique biology of these organisms. Our work seeks to expand our understanding of eukaryotic diversity and identify specific features that can be targeted to treat parasite infections. For more information on our work, visit iBiology.org for Sebastian’s lectures on Toxoplasma and other stories of cutting-edge research in the life sciences, available for free to a global audience.
How parasites persist
Gabriella receives award at ABRCMS
November 17, 2019. Showcasing the work she completed during her semester as an undergraduate researcher in our lab, Gabriella received a Presentation Award during the Annual Biomedical Research Conference for Minority Students. Next stop graduate school!
Lab members complete half marathon
November 3, 2019. Liz, Ben, Tyler and Sebastian all survived and completed the Cambridge Half Marathon collecting the first medals of the Lourido Lab Running Club.
Ben & Tyler receive MPM awards
October 23, 2019. For their presentations at the Molecular Parasitology Meeting in Woods Hole, Ben and Tyler received awards for Best Full Length Talk and Best Poster, respectively. As part of the award, Ben will present his work at the annual meeting of the American Society for Tropical Medicine and Hygiene.
Changes in cytosolic calcium regulate eukaryotic cellular responses as diverse as membrane repair and muscle contraction. In apicomplexan parasites, calcium regulates motility in part through the regulation of adhesin exocytosis and myosin-motor function. We seek to understand the molecular details of these processes, examining both the events that lead to cytosolic calcium changes and the signaling events that follow them.
We are interested in how calcium signals are decoded by protein kinases, and in particular the role of calcium-dependent protein kinases (CDPKs) as the primary calcium-responsive kinases in parasites. Our work, and that of many others, has defined diverse roles for these kinases in regulating important events during the life cycle of apicomplexans. We have recently used alpaca-derived single-domain antibodies to probe the structure of CDPKs, defining a new mode of allosteric inhibition. We continue to develop biochemical methods to study these kinases, in addition to chemical-genetic approaches to study their function in vivo.
We have engineered a panel of strains to study individual CDPKs. This approach relies on mutating the “gatekeeper” residue that restricts the depth of the ATP-binding pocket. This allows us to specifically inhibit or identify the targets of individual kinases. Using this approach, we have previously elucidated the distinct roles of TgCDPK1 and TgCDPK3 during the T. gondii lytic cycle. We continue to investigate the functions of these and other CDPKs, relying in part on phospho-proteomic methods to identify specific kinase targets.
Much of our work is made possible through a variety of genome-engineering methods. We are interested in developing new methods to enable efficient functional analysis of parasite genes and polymorphisms. Our lab was among the first to adapt CRISPR/Cas9 to engineer the T. gondii genome, and our plasmids are available to anyone through Addgene. We continue to improve these systems to enable genome-scale screening in parasites, which will allow exploration of the multitude of apicomplexan genes with unknown functions.
Sebastian Lourido Principal Investigator
Gabrielle McCauley Administrative Lab Manager
Saima Sidik Research Associate
Emily Shortt Lab Manager
Joanna Q. Lin UROP
Kylee T. Carden UROP
Nicole Haseley UROP
Ben Waldman Doctoral Student
Benedikt Markus Doctoral Student
Tyler Smith Doctoral Student
Alice Herneisen Doctoral Student
Alex Chan Doctoral Student
Chris Giuliano Doctoral Student
Elizabeth Boydston Postdoctoral Fellow
Functional and Computational Genomics Reveal Unprecedented Flexibility in Stage-Specific Toxoplasma Metabolism.
Krishnan A, Kloehn J, Lunghi M, Chiappino-Pepe A, Waldman BS, Nicolas D, Varesio E, Hehl A, Lourido S, Hatzimanikatis V, Soldati-Favre D.
Cell Host Microbe. 2020 Jan 27. pii: S1931-3128(20)30041-X.
Waldman BS, Schwarz D, Wadsworth II MS, Saeij JP, Shalek AK, Lourido S.
Cell. 2020 Jan 10. pii: S0092-8674(19)31375-3.
Plate-Based Quantification of Stimulated Toxoplasma Egress.
Shortt E, Lourido S.
Methods Mol Biol. 2020;2071:171-186.
High-Throughput Measurement of Microneme Secretion in Toxoplasma gondii.
Brown KM, Sibley LD, Lourido S.
Methods Mol Biol. 2020;2071:157-169.