An Analysis of LCAT in Regards to Egress in Toxoplasma gondii

Toxoplasma gondii;microbiology;Microbiology and Immunology;Health Sciences;Microbiology & Immunology

Schultz, AricSwanson, Joel A ;

University of Michigan

关键词: Toxoplasma gondii;    microbiology;    Microbiology and Immunology;    Health Sciences;    Microbiology & Immunology;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/144109/aricj_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Egress is a crucial phase of the Toxoplasma gondii intracellular lytic cycle. This is a process that drives inflammation and is strongly associated with the pathogenesis observed during toxoplasmosis. Despite the link between this process and virulence, little is known about egress on a mechanistic or descriptive level. Previously published work suggested that the parasite utilizes a phospholipase, lecithin-cholesterol acyl- transferase (LCAT), for contributions to parasite growth, virulence, and egress. LCAT is secreted from the parasite’s dense granules, but unlike other LCAT orthologues, this enzyme is proteolytically processed into two fragments. This processing is predicted to occur within a unique 140 amino acid insertion found inside LCAT’s conserved catalytic domain. Here we present evidence from several independent mutant parasite lines confirming a role for LCAT in efficient egress, although no defects in growth or virulence were apparent. We also show via genetic complementation that the catalytic activity of LCAT is required for its role in parasite egress. Additionally, a genetically encoded calcium sensor revealed a potential delay in calcium signaling during egress in parasites lacking LCAT. This work solidifies the contribution of LCAT to egress of T. gondii tachyzoites and identifies a new connection in the calcium signaling network.