PSME2 Human

The proteasome is composed of a 20S core and a 19S regulator. The 20S core is made up of four rings of 28 non-identical subunits, while the 19S regulator consists of a base and a lid. The 20S core is responsible for the proteolytic activity, and the 19S regulator recognizes ubiquitinated proteins and unfolds them for degradation .

PA28β is part of the 11S regulator complex, also known as the PA28 complex, which can replace the 19S regulator in the proteasome. The 11S regulator is composed of three alpha and three beta subunits, forming a heterohexameric ring. This complex is particularly important in the immunoproteasome, a modified form of the proteasome that processes class I MHC peptides .

PA28β plays a significant role in the immune system. It is induced by gamma-interferon and is involved in the processing of antigens for presentation on MHC class I molecules. This process is crucial for the immune response, as it allows the immune system to recognize and eliminate infected or malignant cells .

Additionally, PA28β is involved in various cellular processes, including cell cycle regulation and apoptosis. It facilitates the interaction between MDM2 and p53, promoting the ubiquitination and degradation of p53, which limits its accumulation and inhibits apoptosis after DNA damage .

Mutations or dysregulation of the PSME2 gene can be associated with certain diseases. For instance, it has been linked to Familial Apolipoprotein C-II Deficiency, a rare genetic disorder that affects lipid metabolism . Moreover, the role of PA28β in the immune system makes it a potential target for therapeutic interventions in diseases where the immune response is compromised or dysregulated .

Recombinant PA28β is used in research to study its function and role in the proteasome and immune system. Understanding the mechanisms by which PA28β operates can provide insights into the development of new therapeutic strategies for diseases related to proteasome dysfunction and immune system disorders .