S5A, tagged

Background: RPN10 (Regulatory Particle Non-ATPase 10, also known as S5a) is a subunit of the 19S regulatory particle of the proteasome. RPN10 functions as a receptor for polyubiquitylated proteins, recognizing ubiquitin chains and the shuttle factor Ubiquilin-2, which bind to its ubiquitin-interacting motifs (UIMs). Beyond its role in proteolysis, RPN10 participates in regulating proteasome assembly and activity, maintaining cellular protein homeostasis. Its activity is crucial for various biological processes, including cell cycle regulation, stress responses, and signal transduction. Dysregulation or mutations in RPN10 can impair proteasome function, potentially leading to accumulation of defective proteins and contributing to diseases such as cancer, neurodegeneration, and immune disorders. In vitro, S5a can be ubiquitylated by many E3s including multimeric and monomeric RING’s, U-box and HECT domain ligases.