SWP5, a Spore Wall Protein, Interacts with Polar Tube Proteins in the Parasitic Microsporidian Nosema bombycis

Li, Zhi; Pan, Guoqing; Tian, Li; Huang, Wei; Chen, Jie; Geng, Lina; Yang, Donglin; Wang, Linling; Zhou, Zeyang

doi:10.1128/ec.05127-11

Cited by 74 publications

(80 citation statements)

References 43 publications

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“…Recently, a number of studies have shown that NbSWP5 localizes to the exospore and polar tube. NbSWP5 was demonstrated to protect spores from phagocytic uptake (23) and to interact with PTP2 and PTP3; it may also play an important role in supporting the structural integrity of the spore wall and modulating the process of N. bombycis infection (22). This study showed that SWP9 and SWP7 not only localized to the spore wall, but also localized to the polar tube.…”

Section: Discussionmentioning

confidence: 65%

“…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)(22)(23), three endosporal proteins (21,24,25), and a BAR-2 spore wall protein (26) have been characterized. In addition, several spore wall proteins that adhere to host cells via a heparin-binding motif (HBM) and interact with sulfated glycosaminoglycans (GAGs) of the host cell surface have been identified (20,24,27,28).…”

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confidence: 99%

“…(ii) To determine whether SWP9 coimmunoprecipitates with SWP7, we performed experiments on total mature-spore proteins. The immunoprecipitation procedure was as previously described (22,47). In brief, total mature-spore proteins were agitated overnight at 4°C with 20 g of rabbit anti-SWP9 or anti-SWP7 antibody with protein A plus G agarose beads (Beyotime, Chongqing, China).…”

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confidence: 99%

“…Polyclonal antibody production and immunoblotting protocols to detect NbSWP9 and NbSWP7 in the total protein of N. bombycis have been previously described (21,22,24). In short, rabbits and mice were injected with recombinant rSWP9 -glutathione S-transferase (GST) and rSWP7-His proteins, respectively.…”

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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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Section: Discussionmentioning

confidence: 65%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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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

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“…In addition, 9 spore wall proteins have been identified in N. bombycis. N. bombycis SWP25 (NbSWP25), NbSWP26, NbSWP30, and NbSWP16 are endosporal proteins, and NbSWP32 and NbSWP5 are exosporal proteins (20)(21)(22)(23)(24)(25)(26). Furthermore, NbSWP7 and NbSWP9 are colocalized in both the exospore and the endospore of the spore wall (27).…”

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Interaction between SWP9 and Polar Tube Proteins of the Microsporidian Nosema bombycis and Function of SWP9 as a Scaffolding Protein Contribute to Polar Tube Tethering to the Spore Wall

Yang

Pan²,

Peng

et al. 2017

Infect Immun

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All microsporidia possess a unique, highly specialized invasion mechanism that involves the polar tube and spore wall. The interaction between spore wall proteins (SWPs) and polar tube proteins (PTPs) in the formation, arrangement, orderly orientation, and function of the polar tube and spore wall remains to be determined. This study was undertaken to examine the protein interactions of Nosema bombycis SWP7 (NbSWP7), NbSWP9, and PTPs. Coimmunoprecipitation, liquid chromatographytandem mass spectrometry (LC-MS/MS), and yeast two-hybrid data demonstrated that NbSWP9, but not NbSWP7, interacts with NbPTP1 and NbPTP2. Furthermore, immunoelectron microscopy (IEM) showed that NbSWP9 was localized mainly in the developing polar tube of sporoblasts, while NbSWP7 was found randomly in the cytoplasm. However, both NbSWP9 and NbSWP7 were located in the polar tube and spore wall of N. bombycis mature spores. The reason why NbSWP7 was localized to the polar tube may be due to the interaction between NbSWP9 and NbSWP7. Interestingly, the majority of NbSWP9, but not NbSWP7, accumulated in the beginning part of the extruded polar tube and the ruptured spore wall called the anchoring disk (AD) when the mature spores germinated under weak-alkaline environmental stimulation. Additionally, anti-NbSWP9 antibody reduced spore germination in a dose-dependent manner. In conclusion, our study further confirmed that NbSWP9 is a scaffolding protein that not only anchors and holds the polar tube but also tethers the polar tube to the spore wall.

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The Microsporidian Polar Tube and Spore Wall

et al. 2014

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SWP5, a Spore Wall Protein, Interacts with Polar Tube Proteins in the Parasitic Microsporidian Nosema bombycis

Cited by 74 publications

References 43 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

Interaction between SWP9 and Polar Tube Proteins of the Microsporidian Nosema bombycis and Function of SWP9 as a Scaffolding Protein Contribute to Polar Tube Tethering to the Spore Wall

The Microsporidian Polar Tube and Spore Wall

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