PPIG (peptidylprolyl isomerase G) is a peptidyl prolyl isomerase that catalyzes cis-trans isomerization of proline imidic peptide bonds, facilitating protein folding and assisting in protein transport and assembly 1. As a nuclear cyclophilin and member of the spliceophilin family, PPIG localizes to nuclear specks and functions as a component of spliceosomal complexes involved in pre-mRNA splicing regulation 1. PPIG demonstrates dual functionality in both protein folding and RNA processing, binding to RNA and proteins within the nucleus and cytoplasm 1. Clinically, PPIG dysregulation has been implicated in multiple diseases. In colorectal cancer, mutated PPIG was linked to widespread splicing dysregulation and tumor-associated processes, with functional validation confirming its critical role in modulating RNA splicing during tumorigenesis 2. Additionally, PPIG was identified as a candidate therapeutic target for diabetic microangiopathy through genome-wide Mendelian randomization analysis, suggesting involvement in immune-related pathways relevant to disease pathogenesis 3. In psoriasis, altered PPIG expression contributes to aberrant mRNA maturation of disease-associated EDA+ fibronectin, with siRNA silencing studies demonstrating its participation in splicing regulation of this pathogenic variant 4. These findings position PPIG as a potential therapeutic target in cancer and metabolic/inflammatory diseases.