scholarly journals The apical annuli of Toxoplasma gondii are composed of coiled‐coil and signalling proteins embedded in the inner membrane complex sutures

2019 ◽  
Vol 22 (1) ◽  
Author(s):  
Klemens Engelberg ◽  
Chun‐Ti Chen ◽  
Tyler Bechtel ◽  
Victoria Sánchez Guzmán ◽  
Allison A. Drozda ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Coiled Coil ◽  
Inner Membrane ◽  
Membrane Complex ◽  
Inner Membrane Complex

scholarly journals Identification and Molecular Dissection of IMC32, a Conserved Toxoplasma Inner Membrane Complex Protein That Is Essential for Parasite Replication

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Juan A. Torres ◽  
Rebecca R. Pasquarelli ◽  
Peter S. Back ◽  
Andy S. Moon ◽  
Peter J. Bradley
Keyword(s):  
Toxoplasma Gondii ◽  
Coiled Coil ◽  
Inner Membrane ◽  
Content Type ◽  
Apicomplexan Parasites ◽  
Conserved Regions ◽  
Membrane Complex ◽  
Parasite Survival ◽  
Parasite Replication ◽  
Inner Membrane Complex

ABSTRACT The inner membrane complex (IMC) is a unique organelle of apicomplexan parasites that plays critical roles in parasite motility, host cell invasion, and replication. Despite the common functions of the organelle, relatively few IMC proteins are conserved across the phylum and the precise roles of many IMC components remain to be characterized. Here, we identify a novel component of the Toxoplasma gondii IMC (IMC32) that localizes to the body portion of the IMC and is recruited to developing daughter buds early during endodyogeny. IMC32 is essential for parasite survival, as its conditional depletion results in a complete collapse of the IMC that is lethal to the parasite. We demonstrate that localization of IMC32 is dependent on both an N-terminal palmitoylation site and a series of C-terminal coiled-coil domains. Using deletion analyses and functional complementation, we show that two conserved regions within the C-terminal coiled-coil domains play critical roles in protein function during replication. Together, this work reveals an essential component of parasite replication that provides a novel target for therapeutic intervention of T. gondii and related apicomplexan parasites. IMPORTANCE The IMC is an important organelle that apicomplexan parasites use to maintain their intracellular lifestyle. While many IMC proteins have been identified, only a few central players that are essential for internal budding have been described and even fewer are conserved across the phylum. Here, we identify IMC32, a novel component of the Toxoplasma gondii IMC that localizes to very early daughter buds, indicating a role in the early stages of parasite replication. We then demonstrate that IMC32 is essential for parasite survival and pinpoint conserved regions within the protein that are important for membrane association and daughter cell formation. As IMC32 is unique to these parasites and not present in their mammalian hosts, it serves as a new target for the development of drugs that exclusively affect these important intracellular pathogens.

scholarly journals Raft microdomain localized in the luminal leaflet of inner membrane complex of living Toxoplasma gondii

2021 ◽  
Vol 100 (2) ◽  
pp. 151149
Author(s):  
Rikako Konishi ◽  
Yuna Kurokawa ◽  
Kanna Tomioku ◽  
Tatsunori Masatani ◽  
Xuenan Xuan ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Inner Membrane ◽  
Membrane Complex ◽  
Inner Membrane Complex

scholarly journals Identification of the membrane receptor of a class XIV myosin in Toxoplasma gondii

2004 ◽  
Vol 165 (3) ◽  
pp. 383-393 ◽  
Author(s):  
Elizabeth Gaskins ◽  
Stacey Gilk ◽  
Nicolette DeVore ◽  
Tara Mann ◽  
Gary Ward ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Protein Complex ◽  
Integral Membrane Protein ◽  
Gliding Motility ◽  
Host Cells ◽  
Inner Membrane ◽  
Apicomplexan Parasites ◽  
Membrane Complex ◽  
Inner Membrane Complex ◽  
Two Stages

Apicomplexan parasites exhibit a unique form of substrate-dependent motility, gliding motility, which is essential during their invasion of host cells and during their spread between host cells. This process is dependent on actin filaments and myosin that are both located between the plasma membrane and two underlying membranes of the inner membrane complex. We have identified a protein complex in the apicomplexan parasite Toxoplasma gondii that contains the class XIV myosin required for gliding motility, TgMyoA, its associated light chain, TgMLC1, and two novel proteins, TgGAP45 and TgGAP50. We have localized this complex to the inner membrane complex of Toxoplasma, where it is anchored in the membrane by TgGAP50, an integral membrane glycoprotein. Assembly of the protein complex is spatially controlled and occurs in two stages. These results provide the first molecular description of an integral membrane protein as a specific receptor for a myosin motor, and further our understanding of the motile apparatus underlying gliding motility in apicomplexan parasites.

scholarly journals Gliding Associated Proteins Play Essential Roles during the Formation of the Inner Membrane Complex of Toxoplasma gondii

2016 ◽  
Vol 12 (2) ◽  
pp. e1005403 ◽  
Author(s):  
Clare R. Harding ◽  
Saskia Egarter ◽  
Matthew Gow ◽  
Elena Jiménez-Ruiz ◽  
David J. P. Ferguson ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Inner Membrane ◽  
Membrane Complex ◽  
Associated Proteins ◽  
Inner Membrane Complex

scholarly journals N-terminal palmitoylation is required for Toxoplasma gondii HSP20 inner membrane complex localization

2013 ◽  
Vol 1833 (6) ◽  
pp. 1329-1337 ◽  
Author(s):  
M.G. De Napoli ◽  
N. de Miguel ◽  
M. Lebrun ◽  
S.N.J. Moreno ◽  
S.O. Angel ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Inner Membrane ◽  
Membrane Complex ◽  
Inner Membrane Complex

A cytochemistry study of the inner membrane complex of the pellicle of tachyzoites of Toxoplasma gondii

1997 ◽  
Vol 83 (3) ◽  
pp. 252-256 ◽  
Author(s):  
E. J. T. de Melo ◽  
W. de Souza ◽  
E. J. T. de Melo ◽  
W. de Souza
Keyword(s):  
Toxoplasma Gondii ◽  
Inner Membrane ◽  
Membrane Complex ◽  
Inner Membrane Complex

scholarly journals Toxoplasma gondii Hsp20 is a stripe-arranged chaperone-like protein associated with the outer leaflet of the inner membrane complex

2008 ◽  
Vol 100 (8) ◽  
pp. 479-489 ◽  
Author(s):  
Natalia Miguel ◽  
Maryse Lebrun ◽  
Aoife Heaslip ◽  
Ke Hu ◽  
Con J. Beckers ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Inner Membrane ◽  
Membrane Complex ◽  
Outer Leaflet ◽  
Inner Membrane Complex

scholarly journals A photoactivatable crosslinking system reveals protein interactions in the Toxoplasma gondii inner membrane complex

PLoS Biology ◽  
2019 ◽  
Vol 17 (10) ◽  
pp. e3000475 ◽  
Author(s):  
Charles Paul Choi ◽  
Andy Seong Moon ◽  
Peter Sungmin Back ◽  
Yasaman Jami‐Alahmadi ◽  
Ajay Amar Vashisht ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Protein Interactions ◽  
Inner Membrane ◽  
Membrane Complex ◽  
Inner Membrane Complex

scholarly journals The apical annuli of Toxoplasma gondii are composed of coiled-coil and signaling proteins embedded in the IMC sutures

2019 ◽  
Author(s):  
Klemens Engelberg ◽  
Chun-Ti Chen ◽  
Tyler Bechtel ◽  
Victoria Sánchez Guzmán ◽  
Allison A. Drozda ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Coiled Coil ◽  
Super Resolution ◽  
Building Blocks ◽  
Signaling Proteins ◽  
Waste Products ◽  
Membrane Complex ◽  
Inner Membrane Complex

AbstractThe apical annuli are among the most intriguing and understudied structures in the cytoskeleton of the apicomplexan parasite Toxoplasma gondii. We mapped the proteome of the annuli in Toxoplasma by reciprocal proximity biotinylation (BioID), and validated five apical annuli proteins (AAP1-5), Centrin2 and a methyltransferase (AAMT). Moreover, Inner Membrane Complex (IMC) suture proteins connecting the alveolar vesicles were also detected and support annuli residence within the sutures. Super-resolution microscopy (SR-SIM) identified a concentric organization comprising four rings with diameters ranging from 200-400 nm. The high prevalence of domain signatures shared with centrosomal proteins in the AAPs together with Centrin2 suggest that the annuli are related and/or derived from the centrosomes. Phylogenetic analysis revealed the AAPs are conserved narrowly in Coccidian, apicomplexan parasites that multiply by an internal budding mechanism. This suggests a role in replication, for example, to provide pores in the mother IMC permitting exchange of building blocks and waste products. However, presence of multiple signaling domains and proteins are suggestive of additional functions. Knockout of AAP4, the most conserved compound forming the largest ring-like structure, modestly decreased parasite fitness in vitro but had no significant impact on acute virulence in vivo. In conclusion, the apical annuli are composed of coiled-coil and signaling proteins assembled in a pore-like structure crossing the IMC barrier maintained during internal budding.

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