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The Sec1/Munc18‐like proteins TgSec1 and TgVps45 play pivotal roles in assembly of the pellicle and sub‐pellicle network in Toxoplasma gondii
Author(s) -
Cao Shinuo,
Chen Heming,
Liang Xiaohan,
Fu Jiawen,
Wang Shida,
Zheng Jun,
Zhang Zhaoxia,
Pang Yu,
Wang Jingfei,
Shen Bang,
Jia Honglin
Publication year - 2020
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14411
Subject(s) - biology , microbiology and biotechnology , degron , vesicle fusion , vesicle , organelle , lipid bilayer fusion , snare complex , golgi apparatus , vesicular transport protein , transport protein , endosome , toxoplasma gondii , syntaxin , synaptic vesicle , endoplasmic reticulum , biochemistry , genetics , gene , membrane , ubiquitin ligase , ubiquitin , antibody , intracellular
Summary Post‐Golgi vesicle trafficking is indispensable for precise movement of proteins to the pellicle, the sub‐pellicle network and apical secretory organelles in Apicomplexa. However, only a small number of molecular complexes involved in trafficking, tethering and fusion of vesicles have been identified in Toxoplasma gondii . Consequently, it is unclear how complicated vesicle trafficking is accomplished in this parasite. Sec1/Munc18‐like (SM) proteins are essential components of protein complexes involved in vesicle fusion. Here, we found that depletion of the SM protein TgSec1 using an auxin‐inducible degron‐based conditional knockout strategy led to mislocalization of plasma membrane proteins. By contrast, conditional depletion of the SM protein TgVps45 led to morphological changes, asymmetrical loss of the inner membrane complex and defects in nucleation of sub‐pellicular microtubules, polarization and symmetrical assembly of daughter parasites during repeated endodyogeny. TgVps45 interacts with the SNARE protein TgStx16 and TgVAMP4‐1. Conditional ablation of TgStx16 causes the similar growth defect like TgVps45 deficiency suggested they work together for the vesicle fusion at TGN. These findings indicate that these two SM proteins are crucial for assembly of pellicle and sub‐pellicle network in T. gondii respectively.