NSP3 (rotavirus)

NSP3 (Rotavirus)

A reconstruction of the rotavirus particle. The outer layer is removed to show the inner capsid and the RNA genome.

NSP3 or Nonstructural protein 3 is a protein encoded by the rotavirus genome. It is one of the six nonstructural proteins that the virus synthesizes during the course of infection. NSP3 plays a crucial role in the virus's replication cycle, particularly in the synthesis of viral RNA.

Structure[edit | edit source]

NSP3 is a 37-kDa protein that forms homodimers in infected cells. The protein has a unique 'T'-shaped structure, with a globular domain at the top of the 'T' and a coiled-coil stem. The globular domain is responsible for binding to the viral RNA, while the coiled-coil stem is involved in protein-protein interactions.

Function[edit | edit source]

The primary function of NSP3 is to hijack the host cell's protein synthesis machinery for the benefit of the virus. It does this by binding to the 3' end of viral mRNAs and promoting their translation at the expense of cellular mRNAs. This results in a shut-off of host protein synthesis and a redirection of the translation apparatus towards the synthesis of viral proteins.

NSP3 also interacts with various host proteins, including eIF4G, PABP, and the 40S ribosomal subunit. These interactions facilitate the translation of viral mRNAs and contribute to the cytopathic effect of the virus.

Role in Disease[edit | edit source]

As a key player in the replication of rotavirus, NSP3 is directly involved in the pathogenesis of rotavirus infection. The protein's ability to shut off host protein synthesis and redirect the translation apparatus towards viral proteins contributes to the cytopathic effect of the virus and the symptoms of the disease.