EnP1 and EnP2, two proteins associated with the Encephalitozoon cuniculi endospore, the chitin-rich inner layer of the microsporidian spore wall

Peuvel-Fanget, Isabelle; Polonais, Valérie; Brosson, Damien; Texier, Catherine; Kuhn, Lauriane; Peyret, Pierre; Vivarès, Christian P.; Delbac, Frédéric

doi:10.1016/j.ijpara.2005.10.005

Cited by 61 publications

(59 citation statements)

References 28 publications

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“…However, few studies have reported on the interactions between spore wall proteins (SWPs) and the DCSCs in microsporidia. At present, several spore wall proteins that are localized to the exospore or endospore have been identified in the genus Encephalitozoonidae (14,(16)(17)(18)(19)(20). For N. bombycis, only two exosporal proteins (21-23), three endosporal proteins (21,24,25), and a BAR-2 spore wall protein (26) have been characterized.…”

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Interaction and Assembly of Two Novel Proteins in the Spore Wall of the Microsporidian Species Nosema bombycis and Their Roles in Adherence to and Infection of Host Cells

et al. 2015

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Microsporidia are obligate intracellular parasites with rigid spore walls that protect against various environmental pressures. Despite an extensive description of the spore wall, little is known regarding the mechanism by which it is deposited or the role it plays in cell adhesion and infection. In this study, we report the identification and characterization of two novel spore wall proteins, SWP7 and SWP9, in the microsporidian species Nosema bombycis. SWP7 and SWP9 are mainly localized to the exospore and endospore of mature spores and the cytoplasm of sporonts, respectively. In addition, a portion of SWP9 is targeted to the spore wall of sporoblasts earlier than SWP7 is. Both SWP7 and SWP9 are specifically colocalized to the spore wall in mature spores. Furthermore, immunoprecipitation, far-Western blotting, unreduced SDS-PAGE, and yeast two-hybrid data demonstrated that SWP7 interacted with SWP9. The chitin binding assay showed that, within the total spore protein, SWP9 and SWP7 can bind to the deproteinated chitin spore coats (DCSCs) of N. bombycis. However, binding of the recombinant protein rSWP7-His to the DCSCs is dependent on the combination of rSWP9 -glutathione S-transferase (GST) with the DCSCs. Finally, rSWP9-GST, anti-SWP9, and anti-SWP7 antibodies decreased spore adhesion and infection of the host cell. In conclusion, SWP7 and SWP9 may have important structural capacities and play significant roles in modulating host cell adherence and infection in vitro. A possible major function of SWP9 is as a scaffolding protein that supports other proteins (such as SWP7) that form the integrated spore wall of N. bombycis.M icrosporidia, which infect numerous vertebrate and invertebrate species, are a specific group of obligate spore-forming, intracellular, and unicellular eukaryotic protists (1). The microsporidian species Nosema bombycis causes pebrine, a disease that was common in Europe, America, and Asia during the mid19th century and still causes heavy losses in silk-producing countries, such as China and India (1). It was first recognized in 1857 by Nägeli (2). Recently, phylogenetic analyses based on conserved proteins (3-5), ribosomal DNA (rDNA) sequences (6, 7), and complete sequencing of the Encephalitozoon cuniculi genome (8) have suggested that microsporidia, which undergo a highly reductive evolution, are closely related to fungi (9). However, the N. bombycis genome has greatly expanded due to transposable elements and gene duplications (10).The microsporidian spore wall, which is usually comprised of an electron-dense proteinaceous outer layer (exospore) of 25 to 30 nm and an electron-transparent chitinous inner layer (endospore) of 30 to 35 nm, maintains the spore's morphology and helps the mature spore resist the outer environment (11-13). Although chitin is the major component of the spore wall, only one chitin-associated protein has been identified. The chitin deacetylase activity of E. cuniculi (EcCDA) has been confirmed to be expressed during sporogonic stages (14). Currently, the deprot...

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Interaction and Assembly of Two Novel Proteins in the Spore Wall of the Microsporidian Species Nosema bombycis and Their Roles in Adherence to and Infection of Host Cells

et al. 2015

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“…However, little is currently known about the components of the spore wall. Only seven spore wall proteins in E. cuniculi and E. intestinalis were identified by monoclonal or polyclonal antibodies (Bohne et al, 2000;Brosson et al, 2005;Peuvel-Fanget et al, 2006;Southern et al, 2007;Xu et al, 2006;Hayman et al, 2001). Among fourteen hypothetical spore wall proteins from N. Bombycis deposited in GenBank data, only five complete spore wall proteins have been identified, which contain two endosporal proteins(SWP25 and SWP30) and three exosporal proteins (NbSWP5, SWP26, and SWP32) (Wu et al, 2008;Wu et al, 2009;Li et al, 2009;Cai et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

“…To date, only a total of seven spore wall proteins have been reported in E. cuniculi (Bohne et al, 2000;Brosson et al, 2005;Peuvel-Fanget et al, 2006;Southern et al, 2007;Xu et al, 2006) and Encephalitozoon intestinalis (Southern et al, 2007;Hayman et al, 2001), and four spore wall proteins from N. bombycis including SWP25, SWP30, SWP26 and SWP32 were addressed on the location and function (Wu et al, 2008;Li et al, 2009). In our previous study, we identified an exosporal protein NbSWP5 that can protect spores from phagocytic uptaking by cultured insect cells (Cai et al, 2011).…”

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confidence: 99%

Expression and characterization of a novel spore wall protein from Nosema bombycis

Zhang¹,

Li²,

He³

et al. 2014

Afr. J. Biotechnol.

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Microsporidia are obligate intracellular, eukaryotic, spore-forming parasites. The environmentally resistant spores, which harbor a rigid cell wall, are critical for their survival outside their host cells and host-to-host transmission. The spore wall comprises two major layers: the exospore and the endospore. In Nosema bombycis, five spore wall proteins have been identified which contain two endosporal proteins (SWP25 and SWP30) and three exosporal proteins (NbSWP5, SWP26 and SWP32). In the current study, we identified a novel endosporal protein NbSWP12 with calculated molecular mass of 25.56 kDa and pI of 6.69 using SDS-PAGE and MALDI-TOF MS technique. Followed by gene cloning and protein expression, polyclonal antibody production, indirect immunofluorescence antibody test, and immunoelectron microscopy analysis, the results indicate that this protein is localized to the endospore and has no obvious enhancement on adherence to host cells. The characterization of this novel spore wall protein from N. bombycis may facilitate our further investigation of the relationship between N. bombycis and its host, Bombyx mori.

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“…Homologs of this protein have been identified in Encephalitozoon hellem (5) and Encephalitozoon intestinalis (18). Using proteomic techniques, two endospore-associated proteins, SWP3/ EnP2 and EnP1, were discovered in E. cuniculi (32,45). EnP1 was later localized to the exospore as well and found to mediate adherence to host cells (36).…”

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“…This resulted in the identification of Encephalitozoon cuniculi PTP1 (21,22,24) and SWP3/EnP2 (32,45) as well as PTPs of other Encephalitozoonidae (24) and Glugea americanus (25). In the current study, a shotgun proteomic strategy was employed to identify novel structural components from polar tube and spore wall fractions of Encephalitozoon cuniculi.…”

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Branching Network of Proteinaceous Filaments within the Parasitophorous Vacuole of Encephalitozoon cuniculi and Encephalitozoon hellem

et al. 2011

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The microsporidia are a diverse phylum of obligate intracellular parasites that infect all major animal groups and have been recognized as emerging human pathogens for which few chemotherapeutic options currently exist. These organisms infect every tissue and organ system, causing significant pathology, especially in immune-compromised populations. The microsporidian spore employs a unique infection strategy in which its contents are delivered into a host cell via the polar tube, an organelle that lies coiled within the resting spore but erupts with a force sufficient to pierce the plasma membrane of its host cell. Using biochemical and molecular approaches, we have previously identified components of the polar tube and spore wall of the Encephalitozoonidae. In this study, we employed a shotgun proteomic strategy to identify novel structural components of these organelles in Encephalitozoon cuniculi. As a result, a new component of the E. cuniculi developing spore wall was identified. Surprisingly, using the same approach, a heretofore undescribed filamentous network within the lumen of the parasitophorous vacuole was discovered. This network was also present in the parasitophorous vacuole of Encephalitozoon hellem. Thus, in addition to further elucidating the molecular composition of seminal organelles and revealing novel diagnostic and therapeutic targets, proteomic analysis-driven approaches exploring the spore may also uncover unknown facets of microsporidian biology.

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EnP1 and EnP2, two proteins associated with the Encephalitozoon cuniculi endospore, the chitin-rich inner layer of the microsporidian spore wall

Cited by 61 publications

References 28 publications

Interaction and Assembly of Two Novel Proteins in the Spore Wall of the Microsporidian Species Nosema bombycis and Their Roles in Adherence to and Infection of Host Cells

Interaction and Assembly of Two Novel Proteins in the Spore Wall of the Microsporidian Species Nosema bombycis and Their Roles in Adherence to and Infection of Host Cells

Expression and characterization of a novel spore wall protein from Nosema bombycis

Branching Network of Proteinaceous Filaments within the Parasitophorous Vacuole of Encephalitozoon cuniculi and Encephalitozoon hellem

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