A Novel Galectin-Like Domain from Toxoplasma Gondll Micronemal Protein 1 Assists the Folding, Assembly,and Transport of a Cell-Adhesion Complex.
Saouros, S., Edwards-Jones, B., Reiss, M., Sawmynaden, K., Cota, E., Simpson, P., Dowse, T.J., Jakle, U., Ramboarina, S., Shivarattan, T., Matthews, S., Soldati-Favre, D.(2005) J Biological Chem 280: 38583
- PubMed: 16166092
- DOI: https://doi.org/10.1074/jbc.C500365200
- Primary Citation of Related Structures:
2BVB - PubMed Abstract:
Immediately prior to invasion Toxoplasma gondii tachyzoites release a large number of micronemal proteins (TgMICs) that participate in host cell attachment and penetration. The TgMIC4-MIC1-MIC6 complex was the first to be identified in T. gondii and has been recently shown to be critical in invasion. This study establishes that the N-terminal thrombospondin type I repeat-like domains (TSR1-like) from TgMIC1 function as an independent adhesin as well as promoting association with TgMIC4. Using the newly solved three-dimensional structure of the C-terminal domain of TgMIC1 we have identified a novel Galectin-like fold that does not possess carbohydrate binding properties and redefines the architecture of TgMIC1. Instead, the TgMIC1 Galectin-like domain interacts and stabilizes TgMIC6, which provides the basis for a highly specific quality control mechanism for successful exit from the early secretory compartments and for subsequent trafficking of the complex to the micronemes.
Organizational Affiliation:
Department of Biological Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.