PSMB1 Human

Proteasome Subunit Beta Type 1 (PSMB1), also known as 20S proteasome subunit beta-6, is a crucial component of the proteasome complex in humans. This protein is encoded by the PSMB1 gene and plays a significant role in the degradation of intracellular proteins, which is essential for maintaining cellular homeostasis.

The PSMB1 gene is located on chromosome 6 at band 6q27 . It belongs to the proteasome B-type family, also known as the T1B family. The gene is tightly linked to the TBP (TATA-binding protein) gene and is transcribed in the opposite orientation in both humans and mice . The PSMB1 gene comprises six exons and encodes a protein that is 26.5 kDa in size and composed of 241 amino acids .

The proteasome is a multicatalytic proteinase complex with a highly ordered 20S core structure. This barrel-shaped core structure consists of four axially stacked rings of 28 non-identical subunits: two end rings formed by seven alpha subunits and two central rings formed by seven beta subunits . PSMB1, along with other beta subunits, assembles into these rings to form a proteolytic chamber for substrate degradation .

Proteasomes are distributed throughout eukaryotic cells at high concentrations and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway . The primary function of the proteasome is to degrade damaged or misfolded proteins, thereby maintaining protein quality control within the cell. Additionally, the proteasome plays a crucial role in regulating various biological processes by degrading key regulatory proteins .

An essential function of a modified proteasome, known as the immunoproteasome, is the processing of class I MHC peptides . This modification allows the proteasome to generate peptides that are presented on the cell surface to the immune system, thereby playing a role in immune surveillance.

Mutations or dysregulation of the PSMB1 gene have been associated with several clinical conditions. For example, neurodevelopmental disorders with microcephaly, hypotonia, and absent language have been linked to mutations in the PSMB1 gene . Additionally, the proteasome’s role in degrading misfolded proteins implicates it in various neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases .