COPS9 (COP9 Signalosome Subunit 9): COPS9 is a gene that encodes a protein component of the COP9 signalosome, a complex involved in regulating protein degradation. This complex plays crucial roles in cell cycle regulation, signal transduction, and DNA repair by modulating the ubiquitin-proteasome system, which influences protein stability. The function of COPS9 within this complex underlines its importance in maintaining cellular homeostasis and its potential impact on disease when these processes are disrupted.