G2E3 (G2/M-Phase Specific E3 Ubiquitin Protein Ligase): G2E3 is a gene that encodes an E3 ubiquitin ligase involved in regulating the cell cycle, particularly during the G2/M phase transition. It helps tag proteins for degradation, controlling key regulators of the cell cycle. Dysregulation of G2E3 can lead to cell cycle disruptions and contribute to cancer development.