Identification and partial characterization of a 36 kDa surface protein on Neospora caninum tachyzoites

Parasitology ◽  
1997 ◽  
Vol 115 (4) ◽  
pp. 371-380 ◽  
Author(s):  
A. HEMPHILL ◽  
N. FUCHS ◽  
S. SONDA ◽  
B. GOTTSTEIN ◽  
B. HENTRICH
Keyword(s):  
Host Cell ◽  
Neospora Caninum ◽  
Surface Protein ◽  
Cell Entry ◽  
Dense Granules ◽  
Transmission Electron ◽  
Ionic Detergent ◽  
A Cell ◽  
Host Cell Entry ◽  
Triton X

Neospora caninum, the causative agent of neosporosis, is a recently identified apicomplexan parasite which is structurally and biologically closely related to, but antigenically distinct from, Toxoplasma gondii. Molecules associated with the surfaces of N. caninum tachyzoites are likely to participate in the host cell entry process, could be involved in the interaction of the parasite with the immune system, and they could influence the pathogenesis of neosporosis. Isolated N. caninum tachyzoites were extracted with the non-ionic detergent Triton X–114 and were further analysed using a polyclonal anti-N. caninum antiserum. Immunoblots revealed several reactive bands, 1 of which represented a glycoprotein of approximately 36 kDa (Nc-p36). This molecule was present in 2 isolates of Neospora (NC-1 and Liverpool), but was absent in Toxoplasma (RH-strain) tachyzoites. Immunofluorescence and pre-embedding immunogold transmission electron microscopy employing affinity-purified anti-Nc-p36 antibodies showed that the Nc-p36 is a cell surface-associated protein. Immunogold on-section labelling of LR-White-embedded parasites, fixed prior and at defined time-points after host cell entry, demonstrated the presence of this molecule on the surface as well as within the dense granules of N. caninum tachyzoites.

scholarly journals A structure-based rationale for sialic acid independent host-cell entry of Sosuga virus

2019 ◽  
Vol 116 (43) ◽  
pp. 21514-21520 ◽  
Author(s):  
Alice J. Stelfox ◽  
Thomas A. Bowden
Keyword(s):  
Sialic Acid ◽  
Host Cell ◽  
Receptor Binding ◽  
Cell Attachment ◽  
Cell Entry ◽  
Head Region ◽  
Close Proximity ◽  
Host Cell Attachment ◽  
Host Cell Entry

The bat-borne paramyxovirus, Sosuga virus (SosV), is one of many paramyxoviruses recently identified and classified within the newly established genus Pararubulavirus, family Paramyxoviridae. The envelope surface of SosV presents a receptor-binding protein (RBP), SosV-RBP, which facilitates host-cell attachment and entry. Unlike closely related hemagglutinin neuraminidase RBPs from other genera of the Paramyxoviridae, SosV-RBP and other pararubulavirus RBPs lack many of the stringently conserved residues required for sialic acid recognition and hydrolysis. We determined the crystal structure of the globular head region of SosV-RBP, revealing that while the glycoprotein presents a classical paramyxoviral six-bladed β-propeller fold and structurally classifies in close proximity to paramyxoviral RBPs with hemagglutinin-neuraminidase (HN) functionality, it presents a receptor-binding face incongruent with sialic acid recognition. Hemadsorption and neuraminidase activity analysis confirms the limited capacity of SosV-RBP to interact with sialic acid in vitro and indicates that SosV-RBP undergoes a nonclassical route of host-cell entry. The close overall structural conservation of SosV-RBP with other classical HN RBPs supports a model by which pararubulaviruses only recently diverged from sialic acid binding functionality.

Influenza A virus uses the aggresome processing machinery for host cell entry

Science ◽  
2014 ◽  
Vol 346 (6208) ◽  
pp. 473-477 ◽  
Author(s):  
Indranil Banerjee ◽  
Yasuyuki Miyake ◽  
Samuel Philip Nobs ◽  
Christoph Schneider ◽  
Peter Horvath ◽  
...  
Keyword(s):  
Host Cell ◽  
Influenza A Virus ◽  
Influenza A ◽  
Cell Entry ◽  
Processing Machinery ◽  
Host Cell Entry

Novel Drugs Targeting the SARS-CoV-2/COVID-19 Machinery

2020 ◽  
Vol 20 (16) ◽  
pp. 1423-1433 ◽  
Author(s):  
Ariane Sternberg ◽  
Dwight L. McKee ◽  
Cord Naujokat
Keyword(s):  
Host Cell ◽  
Protein Processing ◽  
Cell Entry ◽  
Genome Replication ◽  
Rna Dependent Rna Polymerase ◽  
Main Protease ◽  
Novel Drugs ◽  
Pathogenic Viruses ◽  
Repurposed Drugs ◽  
Host Cell Entry

Like other human pathogenic viruses, coronavirus SARS-CoV-2 employs sophisticated macromolecular machines for viral host cell entry, genome replication and protein processing. Such machinery encompasses SARS-CoV-2 envelope spike (S) glycoprotein required for host cell entry by binding to the ACE2 receptor, viral RNA-dependent RNA polymerase (RdRp) and 3-chymotrypsin-like main protease (3Clpro/Mpro). Under the pressure of the accelerating COVID-19 pandemic caused by the outbreak of SARS-CoV-2 in Wuhan, China in December 2019, novel and repurposed drugs were recently designed and identified for targeting the SARS-CoV-2 reproduction machinery, with the aim to limit the spread of SARS-CoV-2 and morbidity and mortality due to the COVID-19 pandemic.

scholarly journals Baculovirus Utilizes Cholesterol Transporter NIEMANN–Pick C1 for Host Cell Entry

2019 ◽  
Vol 10 ◽  
Author(s):  
Zhihong Li ◽  
Youpeng Fan ◽  
Junhong Wei ◽  
Xionge Mei ◽  
Qiang He ◽  
...  
Keyword(s):  
Host Cell ◽  
Cell Entry ◽  
Host Cell Entry ◽  
Niemann Pick
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