Non-structural protein 4 (NSP4)

Non-structural protein 4 (NSP4) is a multifunctional viral protein most notably characterized as the first recognized viral enterotoxin, primarily associated with Rotavirus. In Rotavirus, it functions as a viroporin that disrupts host calcium homeostasis by inducing the release of calcium from the endoplasmic reticulum into the cytoplasm, which triggers a cascade leading to secretory diarrhea and facilitates viral morphogenesis [3, 51, 61]. Beyond Rotavirus, NSP4 (or nsp4) is also a critical component of the replication machinery in other viruses, such as SARS-CoV-2, where it interacts with NSP3 to remodel host cell membranes into double-membrane vesicles (DMVs) that serve as protected sites for viral RNA synthesis [5, 11, 44]. As a therapeutic target, NSP4 is being explored for the development of antivirals that can mitigate symptoms of severe gastroenteritis or inhibit the replication of coronaviruses. Small molecule inhibitors like STF-3577 have shown promise in blocking NSP4-mediated membrane rearrangements in SARS-CoV-2, while experimental ion channel blockers and probiotics like Saccharomyces boulardii are investigated for their ability to neutralize the enterotoxigenic effects of Rotavirus NSP4 [49, 61, 74]. Given its essential role in both viral pathogenesis and the replication cycle, NSP4 represents a high-value target for broad-spectrum and virus-specific antiviral strategies.

Other names

NSP4Non-structural glycoprotein 4NCVP5NS28Viral enterotoxin NSP4

Inhibition of viroporin-mediated calcium release from the endoplasmic reticulum, disruption of enterotoxin-induced signaling pathways, and prevention of viral replication organelle formation.