| Primary Identifier | IPR008118 | Type | Family |
| Short Name | Gra2_protein |
| description | Toxoplasma gondii is an obligate intracellular apicomplexan protozoan parasite, with a complex lifestyle involving varied hosts []. It has two phases of growth: an intestinal phase in feline hosts, and an extra-intestinal phase in other mammals. Oocysts from infected cats develop into tachyzoites, and eventually, bradyzoites and zoitocysts in the extraintestinal host []. Transmission of the parasite occurs through contact with infected cats or raw/undercooked meat; in immunocompromised individuals, it can cause severe and often lethal toxoplasmosis. Acute infection in healthy humans can sometimes also cause tissue damage [].The protozoan utilises a variety of secretory and antigenic proteins to invade a host and gain access to the intracellular environment []. These originate from distinct organelles in the T. gondii cell termed micronemes, rhoptries, and dense granules. They are released at specific times during invasion to ensure the proteins are allocated to their correct target destinations []. Dense granule antigens (GRAs) are released from the T. gondii tachyzoitewhile still encapsulated in a host vacuole.Gra2, one of these moieties, israpidly targeted to a network of membranous tubules that connect with thevacuolar membrane []. A recent study into the exact mechanism of Gra2secretion has revealed that the secondary structure of the protein plays amajor role in its targeting and release from the apical pole of the parasitic cell []. Two amphipathic α-helical regions ensure not onlythat association of Gra2 with the host vacuole membrane takes place, but also that it is correctly targeted to the cell posterior, where stabilisingnetworks of tubules form and hold the cell steady in the vacuole. |
