NSP

NSP may refer to:

NSP1 (rotavirus)

NSP1, the product of rotavirus gene 5, is an nonstructural RNA-binding protein that contains a cysteine-rich region and is a component of early replication intermediates. RNA-folding predictions suggest that this region of the NSP1 mRNA can interact with itself, producing a stem-loop structure similar to that found near the 5'-terminus of the NSP1 mRNA.

The carboxyl-half of the rotavirus nonstructural protein NSP1 is not required for virus replication.

NSP1 could play a role in host range restriction.

The cysteine-rich region of NSP1 is not considered essential for genome segment reassortment with heterologous virus.

NSP1 interacts with IRF3 in the infected cell. NSP1 is an antagonist of the IFN-signaling pathway.

Interferon regulatory factor 3 (IRF3) is a key transcription factor involved in the induction of interferon (IFN) in response to viral infection. NSP1 binds to and targets IRF3 for proteasome degradation early post-infection. IRF3 degradation is dependent on the presence of NSP1 and the integrity of the N-terminal zinc-binding domain, coupled with the regulated stability of IRF3 and NSP1 by the proteasome, collectively support the hypothesis that NSP1 is an E3 ubiquitin ligase.

NSP3 (rotavirus)

Rotavirus protein NSP3 (NS34) is bound to the 3' end consensus sequence of viral mRNAs in infected cells.

Four nucleotides are the minimal requirement for RNA recognition by rotavirus non-structural protein NSP3: using short oligoribonucleotides, it was established that the minimal RNA sequence required for binding of NSP3A is GACC.

Rotavirus RNA-binding protein NSP3 interacts with eIF4GI and evicts the poly(A)-binding protein from eIF4F. And NSP3A, by taking the place of PABP on eIF4GI, is responsible for the shut-off of cellular protein synthesis.

Expression of NSP3 in mammalian cells allows the efficient translation of virus-like mRNA: NSP3 forms a link between viral mRNA and the cellular translation machinery and hence is a functional analogue of cellular poly(A)-binding protein.

Site-directed mutagenesis and isothermal titration calorimetry documented that NSP3 and PABP use analogous eIF4G recognition strategies, despite marked differences in tertiary structure.

Using the yeast two-hybrid assay, RoXan a novel cellular protein was found to bind NSP3. The interaction between NSP3 and RoXaN does not impair the interaction between NSP3 and eIF4GI, and a ternary complex made of NSP3, RoXaN, and eIF4G I can be detected in rotavirus-infected cells, implicating RoXaN in translation regulation.

NSP6 (rotavirus)

Gene 11 of Rotavirus encodes a nonstructural protein, NSP5 and also encodes NSP6, from an out of phase open reading frame. In contrast to the other rotavirus non-structural proteins, NSP6 was found to have a high rate of turnover, being completely degraded within 2h of synthesis. NSP6 was found to be a sequence independent nucleic acid binding protein, with similar affinities for ssRNA and dsRNA.

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NSP4 (rotavirus)

The rotavirus nonstructural protein NSP4 was the first viral enterotoxin discovered. It induces diarrhea and causes Ca²⁺-dependent transepithelial secretion.

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NSP2 (rotavirus)

NSP2, is a rotavirus nonstructural RNA-binding protein that accumulates in cytoplasmic inclusions (viroplasms) and is required for genome replication. NSP2 is closely associated in vivo with the viral replicase. The non-structural protein NSP5 plays a role in the structure of viroplasms mediated by its interaction with NSP2.

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