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Characterization of Two EF‐hand Domain‐containing Proteins from Toxoplasma gondii
Author(s) -
Chang Le,
Dykes Eric J.,
Li Jianhua,
Moreno Silvia N.J.,
Hortua Triana Miryam Andrea
Publication year - 2018
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/jeu.12675
Subject(s) - rhoptry , biology , toxoplasma gondii , gene , ef hand , crispr , calcium binding protein , microbiology and biotechnology , mutant , extracellular , genetics , peptide sequence , apicomplexa , calcium , immunology , chemistry , organic chemistry , malaria , antibody , plasmodium falciparum
The universal role of calcium (Ca 2+ ) as a second messenger in cells depends on a large number of Ca 2+ ‐binding proteins ( CBP ), which are able to bind Ca 2+ through specific domains. Many CBP s share a type of Ca 2+ ‐binding domain known as the EF ‐hand. The EF ‐hand motif has been well studied and consists of a helix‐loop‐helix structural domain with specific amino acids in the loop region that interact with Ca 2+ . In Toxoplasma gondii a large number of genes (approximately 68) are predicted to have at least one EF ‐hand motif. The majority of these genes have not been characterized. We report the characterization of two EF ‐hand motif‐containing proteins, Tg GT 1_216620 and Tg GT 1_280480 , which localize to the plasma membrane and to the rhoptry bulb, respectively. Genetic disruption of these genes by CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 ( CRISPR ‐associated protein 9) resulted in mutant parasite clones (Δ tg216620 and Δ tg280480 ) that grew at a slower rate than control cells. Ca 2+ measurements showed that Δ tg216620 cells did not respond to extracellular Ca 2+ as the parental controls while Δ tg280480 cells appeared to respond as the parental cells. Our hypothesis is that Tg GT 1_216620 is important for Ca 2+ influx while Tg GT 1_280480 may be playing a different role in the rhoptries.