Plasmodium sporozoites make a remarkable journey from the mosquito midgut wall to the mammalian liver. It is the overall goal of this proposal to elucidate the role of the sporozoite's major surface protein, the circumsporozoite protein (CSP) in this journey. We have been studying the proteolytic processing of CSP and thus far, have found that processing occurs when sporozoites contact hepatocytes and is required for efficient invasion. Specifically, our data indicate that the amino-terminus of CSP masks the cell-adhesive domain in the carboxy-terminus and that proteolytic cleavage results in removal of the amino-terminus and exposure of this cell-adhesive domain. Overall our data suggest that CSP has two functional domains, each with distinct role(s) during the sporozoite's journey. The goal of this proposal is to continue our structure-function work on this important protein to define the role of each CSP domain in the mammalian host and to identify the protease responsible for CSP cleavage.
The specific aims are: 1) To elucidate the phenotype of sporozoite mutants which expressed only the cleaved form of CSP in the dermis of the mammalian host. Using quantitative PCR, transcriptional profiling and confocal microscopy, we will determine whether N-terminal deletion mutants remain in the skin and begin their development there. 2) To determine the binding properties of each CSP domain by generating mutants in N-terminal residues that we have identified as having potential heparin-binding activity and using biochemical techniques to determine the binding partner of the TSR domain. 3) To identify the protease that cleaves CSP and determine its subcellular location in the sporozoite. These studies will be performed using conditional mutagenesis to delete candidate protease genes and using antisera to localize the proteases in sporozoites. Overall these studies will elucidate how CSP functions in the sporozoite?s journey from mosquito to mammalian host and should open up new avenues for the control and prevention of malaria.
These studies are of relevance to the control and prevention of one of the most important infectious diseases in the world. Malaria continues to impact significantly, children and adults living in tropical and subtropical parts of the world, in part due to drug resistance to our best anti-malarials and to the lack of an effective vaccine. The experiments described in this proposal could provide the basis for new drug therapies and improve upon existing approaches to malaria vaccine development.
|Bunnik, Evelien M; Cook, Kate B; Varoquaux, Nelle et al. (2018) Changes in genome organization of parasite-specific gene families during the Plasmodium transmission stages. Nat Commun 9:1910|
|Dundas, Kirsten; Shears, Melanie J; Sun, Yi et al. (2018) Alpha-v-containing integrins are host receptors for the Plasmodium falciparum sporozoite surface protein, TRAP. Proc Natl Acad Sci U S A 115:4477-4482|
|Dellibovi-Ragheb, Teegan A; Jhun, Hugo; Goodman, Christopher D et al. (2018) Host biotin is required for liver stage development in malaria parasites. Proc Natl Acad Sci U S A 115:E2604-E2613|
|Pal, Priya; Balaban, Amanda E; Diamond, Michael S et al. (2017) Plasmodium falciparum histidine-rich protein II causes vascular leakage and exacerbates experimental cerebral malaria in mice. PLoS One 12:e0177142|
|Aguiar, Anna Caroline C; Figueiredo, Flávio Jr B; Neuenfeldt, Patrícia D et al. (2017) Primaquine-thiazolidinones block malaria transmission and development of the liver exoerythrocytic forms. Malar J 16:110|
|Voss, Christiane; Ehrenman, Karen; Mlambo, Godfree et al. (2016) Overexpression of Plasmodium berghei ATG8 by Liver Forms Leads to Cumulative Defects in Organelle Dynamics and to Generation of Noninfectious Merozoites. MBio 7:|
|Swearingen, Kristian E; Lindner, Scott E; Shi, Lirong et al. (2016) Interrogating the Plasmodium Sporozoite Surface: Identification of Surface-Exposed Proteins and Demonstration of Glycosylation on CSP and TRAP by Mass Spectrometry-Based Proteomics. PLoS Pathog 12:e1005606|
|Moreira, Cristina K; Naissant, Bernina; Coppi, Alida et al. (2016) The Plasmodium PHIST and RESA-Like Protein Families of Human and Rodent Malaria Parasites. PLoS One 11:e0152510|
|Hopp, Christine S; Balaban, Amanda E; Bushell, Ellen S C et al. (2016) Palmitoyl transferases have critical roles in the development of mosquito and liver stages of Plasmodium. Cell Microbiol 18:1625-1641|
|Hopp, Christine S; Sinnis, Photini (2015) The innate and adaptive response to mosquito saliva and Plasmodium sporozoites in the skin. Ann N Y Acad Sci 1342:37-43|
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