Microneme Protein 5 Regulates the Activity of Toxoplasma Subtilisin 1 by Mimicking a Subtilisin Prodomain

Saouros, Savvas; Dou, Zhicheng; Henry, Marie‐Claire; Marchant, Jan; Carruthers, Vern B.; Matthews, Stephen

doi:10.1074/jbc.m112.389825

Cited by 24 publications

(23 citation statements)

References 47 publications

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“…Similar to previously determined family S8 bacterial and mammalian subtilisin propeptide structures (e.g. [42][43][44]) as well as the P. falciparum SUB2 (PfSUB2) propeptide [45] and the stand-alone propeptide mimic TgMIC5 (PDB ID: 2LU2) [7], the core of both SUB1 propeptides comprises two antiparallel alpha helical elements, one of which is slightly kinked, packed against a four-stranded antiparallel beta sheet to produce an overall compact βαβ-βαβ topology (Figure 2b and Supplementary Figure S2).…”

Section: Resultssupporting

confidence: 82%

“…All three proteins (Pleurotus ostreatus peptidase A inhibitor 1, Saccharomyces cerevisiae peptidase B inhibitor and Arabidopsis thaliana subtilisin propeptide like inhibitor 1), display typically potent inhibition of one or more subtilisin-like proteases [3][4][5][6]. A further recently characterised example of a subtilisin propeptidelike mimic is microneme protein 5 (TgMIC5; [7]) of the parasitic protist Toxoplasma gondii, which regulates the activity of a subtilase that 'trims' surface proteins involved in motility of the parasite [8]. The existence of such stand-alone propeptide-like proteins may reflect a process of convergent evolution [9] in which the subtilisin propeptide fold has been adopted to carry out regulatory protease inhibitory functions independent of any chaperone activity.…”

Section: Introductionmentioning

confidence: 99%

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A malaria parasite subtilisin propeptide-like protein is a potent inhibitor of the egress protease SUB1

Tarr

Withers‐Martinez

Flynn

et al. 2020

Biochemical Journal

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Subtilisin-like serine peptidases (subtilases) play important roles in the life cycle of many organisms, including the protozoan parasites that are the causative agent of malaria, Plasmodium spp. As with other peptidases, subtilase proteolytic activity has to be tightly regulated in order to prevent potentially deleterious uncontrolled protein degradation. Maturation of most subtilases requires the presence of an N-terminal propeptide that facilitates folding of the catalytic domain. Following its proteolytic cleavage, the propeptide acts as a transient, tightly bound inhibitor until its eventual complete removal to generate active protease. Here we report the identification of a stand-alone malaria parasite propeptide-like protein, called SUB1-ProM, encoded by a conserved gene that lies in a highly syntenic locus adjacent to three of the four subtilisin-like genes in the Plasmodium genome. Template-based modelling and ab initio structure prediction showed that the SUB1-ProM core structure is most similar to the X-ray crystal structure of the propeptide of SUB1, an essential parasite subtilase that is discharged into the parasitophorous vacuole (PV) to trigger parasite release (egress) from infected host cells. Recombinant Plasmodium falciparum SUB1-ProM was found to be a fast-binding, potent inhibitor of P. falciparum SUB1, but not of the only other essential blood-stage parasite subtilase, SUB2, or of other proteases examined. Mass-spectrometry and immunofluorescence showed that SUB1-ProM is expressed in the PV of blood stage P. falciparum, where it may act as an endogenous inhibitor to regulate SUB1 activity in the parasite.

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Section: Resultssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

A malaria parasite subtilisin propeptide-like protein is a potent inhibitor of the egress protease SUB1

Tarr

Withers‐Martinez

Flynn

et al. 2020

Biochemical Journal

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“…It was shown to be secreted into the surrounding medium. Although TgMIC5 seems to be involved in the maturation of other surface proteins by facilitating their proteolysis, the type of involvement of the parvulin-like domain in those processes is not clear (122,123). Besides that protein, TcPin1 and TcPar45 of T. cruzi, as well as their homologs TbPin1 and TbPar42 of Trypanosoma brucei, are the only parvulins described for protozoan parasites (124)(125)(126)(127).…”

Section: Ppiases Of Parasitic Protozoamentioning

confidence: 99%

Microbial Peptidyl-Prolyl cis / trans Isomerases (PPIases): Virulence Factors and Potential Alternative Drug Targets

Ünal

Steinert

2014

Microbiol Mol Biol Rev

154

146

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SUMMARY Initially discovered in the context of immunomodulation, peptidyl-prolyl cis/trans isomerases (PPIases) were soon identified as enzymes catalyzing the rate-limiting protein folding step at peptidyl bonds preceding proline residues. Intense searches revealed that PPIases are a superfamily of proteins consisting of three structurally distinguishable families with representatives in every described species of prokaryote and eukaryote and, recently, even in some giant viruses. Despite the clear-cut enzymatic activity and ubiquitous distribution of PPIases, reports on solely PPIase-dependent biological roles remain scarce. Nevertheless, they have been found to be involved in a plethora of biological processes, such as gene expression, signal transduction, protein secretion, development, and tissue regeneration, underscoring their general importance. Hence, it is not surprising that PPIases have also been identified as virulence-associated proteins. The extent of contribution to virulence is highly variable and dependent on the pleiotropic roles of a single PPIase in the respective pathogen. The main objective of this review is to discuss this variety in virulence-related bacterial and protozoan PPIases as well as the involvement of host PPIases in infectious processes. Moreover, a special focus is given to Legionella pneumophila macrophage infectivity potentiator (Mip) and Mip-like PPIases of other pathogens, as the best-characterized virulence-related representatives of this family. Finally, the potential of PPIases as alternative drug targets and first tangible results are highlighted.

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“…Protein modeling has been broadly used nowadays [13-15]. It is used to discover the spatial organization of a protein by prediction of molecular interactions, based on the crystal structure of relatively similar amino acid sequences, which may provide relevant data on its function and active sites.…”

Section: Introductionmentioning

confidence: 99%

SAG2A protein from Toxoplasma gondii interacts with both innate and adaptive immune compartments of infected hosts

et al. 2013

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BackgroundToxoplasma gondii is an intracellular parasite that causes relevant clinical disease in humans and animals. Several studies have been performed in order to understand the interactions between proteins of the parasite and host cells. SAG2A is a 22 kDa protein that is mainly found in the surface of tachyzoites. In the present work, our aim was to correlate the predicted three-dimensional structure of this protein with the immune system of infected hosts.MethodsTo accomplish our goals, we performed in silico analysis of the amino acid sequence of SAG2A, correlating the predictions with in vitro stimulation of antigen presenting cells and serological assays.ResultsStructure modeling predicts that SAG2A protein possesses an unfolded C-terminal end, which varies its conformation within distinct strain types of T. gondii. This structure within the protein shelters a known B-cell immunodominant epitope, which presents low identity with its closest phyllogenetically related protein, an orthologue predicted in Neospora caninum. In agreement with the in silico observations, sera of known T. gondii infected mice and goats recognized recombinant SAG2A, whereas no serological cross-reactivity was observed with samples from N. caninum animals. Additionally, the C-terminal end of the protein was able to down-modulate pro-inflammatory responses of activated macrophages and dendritic cells.ConclusionsAltogether, we demonstrate herein that recombinant SAG2A protein from T. gondii is immunologically relevant in the host-parasite interface and may be targeted in therapeutic and diagnostic procedures designed against the infection.

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Microneme Protein 5 Regulates the Activity of Toxoplasma Subtilisin 1 by Mimicking a Subtilisin Prodomain

Cited by 24 publications

References 47 publications

A malaria parasite subtilisin propeptide-like protein is a potent inhibitor of the egress protease SUB1

A malaria parasite subtilisin propeptide-like protein is a potent inhibitor of the egress protease SUB1

Microbial Peptidyl-Prolyl cis / trans Isomerases (PPIases): Virulence Factors and Potential Alternative Drug Targets

SAG2A protein from Toxoplasma gondii interacts with both innate and adaptive immune compartments of infected hosts

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