RNPS1 (RNA binding protein with serine rich domain 1) functions as a versatile regulator of pre-mRNA splicing and post-transcriptional gene expression. The protein serves as a general activator of pre-mRNA splicing, synergizing with SR proteins to enhance both constitutive and alternative splicing events 1. RNPS1 contains three functional domains: an N-terminal serine-rich domain, a central RNA recognition motif (RRM), and a C-terminal arginine/serine/proline-rich domain, which interact with distinct splicing factors including p54, pinin, and hTra2β 2. The protein acts as a peripheral component of the exon junction complex (EJC) and plays a critical role in maintaining splicing fidelity by suppressing aberrant splicing at cryptic splice sites 34. RNPS1 forms diverse splicing-regulatory complexes through its RRM and C-terminal domains to promote correct splicing of vulnerable transcripts 4. The serine-rich domain specifically functions in alternative splicing activation 5. Clinically, RNPS1 is overexpressed in multiple cancers including cervical and head-neck carcinomas, where it promotes oncogenic alternative splicing patterns, enhances tumor cell proliferation and invasion, and contributes to chemoresistance 67. These findings establish RNPS1 as both a guardian of transcriptome integrity and a potential therapeutic target in cancer.