PABPC5 is a cytoplasmic poly(A) binding protein encoded on chromosome X.3 that binds the poly(A) tail of mRNA and participates in cytoplasmic RNA metabolism 1. The protein contains four RNA recognition motif domains and shares 60% amino acid identity with PABPC4 1. Beyond its canonical cytoplasmic localization, PABPC5 undergoes alternative translation initiation to generate a mitochondrial isoform that co-immunoprecipitates with mitochondrial poly(A) polymerase and is reduced upon mitochondrial DNA/RNA depletion, indicating a functional role in organellar RNA metabolism 2. PABPC5 expression is detected in fetal brain and multiple adult tissues 1. Disease relevance includes potential involvement in premature ovarian failure due to proximity to associated translocation breakpoints 1, and PABPC5 deletion has been associated with longer survival in ovarian cancer, possibly through effects on cellular immune response 3. DNA methylation alterations at PABPC5 have been identified in female Crohn's disease patients, suggesting X-linked disease manifestations 4. PABPC5 mutations have been identified as a candidate novel gene correlated with non-small cell lung cancer metastasis 5. However, functional characterization of PABPC5 in these disease contexts remains incomplete.