Psmb4, the proteasome subunit beta type 4, is a non-catalytic subunit for the proteasome assembly. The proteasome system is crucial for protein degradation in cells, and Psmb4 likely contributes to the proper function of this system, which is involved in various cellular processes such as cell cycle regulation, apoptosis, and immune responses [4].

Psmb4 has been found to interact with viral proteins. It can interact with the NS1 protein of influenza A virus (IAV), potentially facilitating its degradation and thus suppressing IAV replication [1]. Psmb4 also interacts with the Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Nsp1α protein, mediating its K63-linked ubiquitination and autolysosomal degradation, and activating the NF-κB signaling pathway to produce type I interferons, restricting PRRSV replication [2]. In the context of cancer, knockdown of Psmb4 significantly inhibits cervical cancer cell proliferation [4]. In epithelial ovarian cancer (EOC), Psmb4 is highly expressed, and its knockdown reduces cell proliferation and NF-κB activity [5]. In bladder cancer, reducing Psmb4 inhibits the angiogenesis and migration of endothelial cells [6]. Regarding myocardial ischemia/reperfusion injury, Psmb4 inhibits cardiomyocyte apoptosis via activating the NF-κB signaling pathway [3].

In conclusion, Psmb4 plays diverse and important roles in multiple biological processes and diseases. Its interactions with viral proteins suggest a role in antiviral defense, while its involvement in cancer cell proliferation and apoptosis in different cancer types, as well as its function in myocardial ischemia/reperfusion injury, indicates its potential as a therapeutic target in these disease areas. The study of Psmb4 using genetic models helps to better understand its functions and provides insights for developing new treatment strategies.