9.A.67.  The Toxoplasma Parasitophorous Vacuole Translocon of Exported Proteins (T-TEX) Family 

The T-TEX complex in the parsitophorous vacuole membrane consists of 3 known proteins, MYR1, MYR2 and MYR3 (Marino et al. 2018). These proteins do not show appreciable sequence similarity with the members of the P (Plasmodium)-TEX family (TC# 3.A.26).

Toxoplasma gondii is an obligate intracellular parasite that can infect virtually all nucleated cells in warm-blooded animals. The ability of Toxoplasma tachyzoites to infect and successfully manipulate its host is dependent on its ability to transport "GRA" proteins that originate in unique secretory organelles called dense granules into the host cell in which they reside (Marino et al. 2018). GRAs have diverse roles in Toxoplasma's intracellular lifecycle, including co-opting crucial host cell functions and proteins, such as the cell cycle, c-Myc and p38 MAP kinase. Some of these GRA proteins, such as GRA16 and GRA24, are secreted into the parasitophorous vacuole (PV) within which Toxoplasma replicates and are transported across the PV membrane (PVM) into the host cell. The MyR1, 2 and 3 proteins have been implicated in this process (Marino et al. 2018).



Marino, N.D., M.W. Panas, M. Franco, T.C. Theisen, A. Naor, S. Rastogi, K.R. Buchholz, H.A. Lorenzi, and J.C. Boothroyd. (2018). Identification of a novel protein complex essential for effector translocation across the parasitophorous vacuole membrane of Toxoplasma gondii. PLoS Pathog 14: e1006828.


TC#NameOrganismal TypeExample

The Toxoplasma parasitophorous vacuole membrane translocon of exported proteins (PTEX).  It consists of three known proteins, MYR1, MYR2 and MYR3 (Marino et al. 2018).

Toxoplasma translocon
MYR1, 732 aas and 3 C-terminal TMSs, S7VVL5
MYR2, 295 aas and 3 TMS, (two N-terminal and one C-terminal), S7WKK8
MYR3, 213 aas and 1 TMS, S7UQ33