GO_REF:0000044

Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt

PMID:25605761

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.

SWP7 is localized to the exospore and endospore of mature N. bombycis spores and colocalizes there with SWP9.

"Both SWP7 and SWP9 are specifically colocalized to the spore wall in mature spores."
SWP7 interacts with SWP9, shown by four independent assays.

"immunoprecipitation, far-Western blotting, unreduced SDS-PAGE, and yeast two-hybrid data demonstrated that SWP7 interacted with SWP9"
Recombinant SWP7 does not bind the deproteinated chitin spore coat on its own; its binding requires SWP9 to be bound first. Chitin binding is therefore not a molecular function of SWP7.

"binding of the recombinant protein rSWP7-His to the DCSCs is dependent on the combination of rSWP9-glutathione S-transferase (GST) with the DCSCs"
Masking SWP7 on the spore surface with antibody reduces adhesion of spores to, and infection of, host cells.

"anti-SWP9, and anti-SWP7 antibodies decreased spore adhesion and infection of the host cell"
The authors' structural claim for SWP7 is hedged, and they frame SWP9 rather than SWP7 as the scaffold.

"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"

PMID:28031263

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.

Immunoelectron microscopy independently places SWP7 in the cytoplasm of sporoblasts and in both the polar tube and the spore wall of mature spores, corroborating all three GOA cellular-component claims.

"both NbSWP9 and NbSWP7 were located in the polar tube and spore wall of N. bombycis mature spores"
SWP7 does not interact with the polar tube proteins PTP1 and PTP2; SWP9 does.

"demonstrated that NbSWP9, but not NbSWP7, interacts with NbPTP1 and NbPTP2"
The authors attribute SWP7's polar tube localization to its being carried there by SWP9.

"The reason why NbSWP7 was localized to the polar tube may be due to the interaction between NbSWP9 and NbSWP7"

PMID:18563739

Proteomic analysis of spore wall proteins and identification of two spore wall proteins from Nosema bombycis (Microsporidia).

The N. bombycis spore wall is a two-layered structure, a glycoprotein-rich exospore over a chitin-rich endospore.

"protected by a thick spore wall composed of a glycoprotein-rich outer layer or exospore and a chitin-rich inner layer or endospore"
Fourteen hypothetical spore wall proteins were recovered from the N. bombycis spore wall by MALDI-TOF MS and LC-MS/MS; SWP7 (HSWP7) was identified among them, and UniProt cites this paper for SWP7 identification by mass spectrometry and subcellular location.

"14 hypothetical spore wall proteins (HSWPs) or peptides were obtained in total"

PMID:29522765

The roles of microsporidia spore wall proteins in the spore wall formation and polar tube anchorage to spore wall during development and infection processes.

The microsporidian spore wall has three layers, the chitinous endospore, the proteinaceous exospore and the plasma membrane.

"a rigid cell wall which consists of three layers: the electron-lucent chitin and protein inner endospore, the outer-electron-dense and mainly proteinaceous exospore and plasma membrane"
Spore wall and polar tube are the structures through which mature spores attach to and infect host cells.

"Spore wall and polar tube are the major apparatuses for mature spores adhering and infecting to the host cells"

file:NOSB1/SWP7/SWP7-uniprot.txt

UniProt B3STP1 SWP7 record (Nosema bombycis strain CQ1)