Apicomplexan parasites rely on a novel form of actin-based motility called gliding, which depends on parasite actin polymerization, to migrate through their hosts and invade cells. However, parasite actins are divergent both in sequence and function and only form short, unstable filaments in contrast to the stability of conventional actin filaments. The molecular basis for parasite actin filament instability and its relationship to gliding motility remain unresolved. We demonstrate that recombinant Toxoplasma (TgACTI) and Plasmodium (PfACTI and PfACTII) actins polymerized into very short filaments in vitro but were induced to form long, stable filaments by addition of equimolar levels of phalloidin. Parasite actins contain a conserved phalloidin-binding site as determined by molecular modeling and computational docking, yet vary in several residues that are predicted to impact filament stability. In particular, two residues were identified that form intermolecular contacts between different protomers in conventional actin filaments and these residues showed non-conservative differences in apicomplexan parasites. Substitution of divergent residues found in TgACTI with those from mammalian actin resulted in formation of longer, m...Continue Reading
Stage-specific expression and genomic organization of the actin genes of the malaria parasite Plasmodium falciparum
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Time-lapse video microscopy of gliding motility in Toxoplasma gondii reveals a novel, biphasic mechanism of cell locomotion
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Unusual kinetic and structural properties control rapid assembly and turnover of actin in the parasite Toxoplasma gondii
Comparative genome analysis reveals a conserved family of actin-like proteins in apicomplexan parasites
Effect of the substitution of muscle actin-specific subdomain 1 and 2 residues in yeast actin on actin function
A malaria parasite formin regulates actin polymerization and localizes to the parasite-erythrocyte moving junction during invasion
Active transcription is required for maintenance of epigenetic memory in the malaria parasite Plasmodium falciparum
Purification of actin from fission yeast Schizosaccharomyces pombe and characterization of functional differences from muscle actin.
An actin cytoskeleton with evolutionarily conserved functions in the absence of canonical actin-binding proteins
Optimizing small molecule inhibitors of calcium-dependent protein kinase 1 to prevent infection by Toxoplasma gondii
Calcium-dependent phosphorylation alters class XIVa myosin function in the protozoan parasite Toxoplasma gondii
Molecular characterization of Toxoplasma gondii formin 3, an actin nucleator dispensable for tachyzoite growth and motility
The toxoplasma Acto-MyoA motor complex is important but not essential for gliding motility and host cell invasion
Toxoplasma gondii profilin acts primarily to sequester G-actin while formins efficiently nucleate actin filament formation in vitro
Cofilin-induced cooperative conformational changes of actin subunits revealed using cofilin-actin fusion protein
Chromerid genomes reveal the evolutionary path from photosynthetic algae to obligate intracellular parasites
Synthetic chondramide A analogues stabilize filamentous actin and block invasion by Toxoplasma gondii
Holding back the microfilament--structural insights into actin and the actin-monomer-binding proteins of apicomplexan parasites
Pivotal and distinct role for Plasmodium actin capping protein alpha during blood infection of the malaria parasite
Genetic crosses and complementation reveal essential functions for the Plasmodium stage-specific actin2 in sporogonic development
Disassembly activity of actin-depolymerizing factor (ADF) is associated with distinct cellular processes in apicomplexan parasites
Plasmodium falciparum coronin organizes arrays of parallel actin filaments potentially guiding directional motility in invasive malaria parasites
Disruption of TgPHIL1 alters specific parameters of Toxoplasma gondii motility measured in a quantitative, three-dimensional live motility assay
Dense granule trafficking in Toxoplasma gondii requires a unique class 27 myosin and actin filaments
Comparative Plasmodium gene overexpression reveals distinct perturbation of sporozoite transmission by profilin
New cell motility model observed in parasitic cnidarian Sphaerospora molnari (Myxozoa:Myxosporea) blood stages in fish
An Apicomplexan Actin-Binding Protein Serves as a Connector and Lipid Sensor to Coordinate Motility and Invasion
Comparative proteomic analysis of different Toxoplasma gondii genotypes by two-dimensional fluorescence difference gel electrophoresis combined with mass spectrometry
Three F-actin assembly centers regulate organelle inheritance, cell-cell communication and motility in Toxoplasma gondii
Differential requirements for cyclase-associated protein (CAP) in actin-dependent processes of Toxoplasma gondii
A function of profilin in force generation during malaria parasite motility independent of actin binding
Cryptosporidium parvum Elongation Factor 1α Participates in the Formation of Base Structure at the Infection Site During Invasion.
Structure of Toxoplasma gondii coronin, an actin-binding protein that relocalizes to the posterior pole of invasive parasites and contributes to invasion and egress
Plasmodium actin is incompletely folded by heterologous protein-folding machinery and likely requires the native Plasmodium chaperonin complex to enter a mature functional state
Toxoplasma gondii F-actin forms an extensive filamentous network required for material exchange and parasite maturation
Near-atomic structure of jasplakinolide-stabilized malaria parasite F-actin reveals the structural basis of filament instability
Structural and mechanistic insights into the function of the unconventional class XIV myosin MyoA from Toxoplasma gondii
Calmodulin-like proteins localized to the conoid regulate motility and cell invasion by Toxoplasma gondii
A mechanism for actin filament severing by malaria parasite actin depolymerizing factor 1 via a low affinity binding interface.
Actin and an unconventional myosin motor, TgMyoF, control the organization and dynamics of the endomembrane network in Toxoplasma gondii.
Babesiosis is caused by parasites of the genus babesia, which are transmitted in nature by the bite of an infected tick. Discover the latest research on babesiosis here.
Actin-binding proteins are a component of the actin cytoskeleton that play essential roles in cellular functions such as regulation of actin polymerization, maintenance of cell polarity, gene expression regulation, cell motility and many more functions. Discover the latest research on actin-binding proteins here.