AUTHOR=Yang Na , Xing Mengen , Ding Yingying , Wang Dawei , Guo Xiaogai , Sang Xiaoyu , Li Jiaqi , Li Chenghuan , Wang Yanhu , Feng Ying , Chen Ran , Wang Xinyi , Jiang Ning , Chen Qijun 

TITLE=The Putative TCP-1 Chaperonin Is an Important Player Involved in Sialic Acid-Dependent Host Cell Invasion by Toxoplasma gondii

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00258

DOI=10.3389/fmicb.2020.00258

ISSN=1664-302X

ABSTRACT=<p>Host cell invasion by <italic>Toxoplasma gondii</italic> is crucial for the survival and proliferation of parasite. The process of <italic>T. gondii</italic> tachyzoite invasion requires interaction between parasite proteins and receptors on the surface of host cells. Sialic acid is one of the important receptors for host cell invasion by <italic>T. gondii</italic>. However, the parasite-derived proteins interacting with sialic acid have not been well characterized. In this study, a novel protein named putative TCP-1 chaperonin (TGME49_318410) in <italic>T. gondii</italic> (TgTCP-1) was targeted and characterized. TgTCP-1 protein colocalized with MIC3 protein, which could be secreted from <italic>T. gondii</italic> tachyzoites, and this protein showed a specific binding activity to sialic acid, and DC and Vero cells <italic>in vitro</italic>. The binding of TgTCP-1 protein to DC and Vero cells were inhibited by either pre-incubation with free sialic acid or neuraminidase treatment of the cells. Moreover, a significant reduction of <italic>T. gondii</italic> invasion in Vero cells was observed after pre-incubation of the cells with recombinant TgTCP-1 protein. These results illustrated that TgTCP-1 is an important molecule involved in sialic acid-dependent host cell invasion by <italic>T. gondii</italic>.</p>