MAGOHB (mago homolog B) functions as a core component of the exon junction complex (EJC), working redundantly with its paralog MAGOH to regulate multiple aspects of mRNA metabolism 1. As part of the EJC, MAGOHB is required for pre-mRNA splicing and participates in the spliceosome assembly process 2. The protein plays essential roles in nonsense-mediated decay (NMD), mRNA export, and translation regulation 12. Mechanistically, MAGOHB forms heterodimers that are imported into the nucleus via the IPO13 importin pathway, where they incorporate into mRNA-bound EJCs during splicing 3. MAGOHB shows clinical significance as a cancer vulnerability, particularly in cells with chromosome 12 loss that affects MAGOH expression, creating a synthetic lethal dependency 3. In melanoma, MAGOHB knockdown decreases NMD activity and promotes apoptosis through upregulation of GADD45A 4. The gene also serves as a diagnostic biomarker, with altered MAGOHB expression in platelets showing promise for pancreatic cancer detection 5. Additionally, MAGOHB expression correlates with immune suppression in clear cell renal cell carcinoma and affects treatment response predictions 6.