RBM38 (RNA binding motif protein 38) is an RNA-binding protein that functions as a tumor suppressor and regulator of post-transcriptional gene expression. RBM38 recognizes specific RNA sequences (G(U/C/A)GUG motifs) through its RRM domain and regulates mRNA stability, splicing, and translation 1. The protein plays critical roles in multiple biological processes including erythropoiesis, where it regulates ferrochelatase expression essential for heme biosynthesis, with deficiency causing microcytic anemia and protoporphyria 2. In cancer biology, RBM38 frequently acts as a tumor suppressor across multiple cancer types, with expression generally lost but rarely mutated in cancers 3. RBM38 forms a negative feedback loop with p63 tumor suppressor, and this regulatory circuit is crucial for tumor suppression and longevity, as compound deficiency extends lifespan while reducing tumor incidence and senescence markers 4. Additionally, RBM38 contributes to DNA damage response through autophagy regulation, where a primate-specific isoform (RBM38c) undergoes K63-linked ubiquitination and interacts with BECN1 to promote autophagy initiation 5. The protein also regulates cardiomyocyte proliferation as part of the CBX7/TARDBP/RBM38 axis 6.