SNRPD2 (small nuclear ribonucleoprotein D2 polypeptide) is a core Sm protein component of the spliceosome, functioning as a structural element within U1, U2, U4, and U5 small nuclear ribonucleoproteins 1. It participates in both pre-catalytic and activated spliceosome complexes, facilitating pre-mRNA splicing and U12-type intron splicing 2. Beyond canonical splicing, SNRPD2 regulates alternative polyadenylation by disrupting PABPN1 phase separation 3 and cooperates with mutant p53 in modulating alternative splicing patterns 4. SNRPD2 is significantly upregulated across multiple cancer types, including hepatocellular carcinoma, ovarian cancer, and colorectal cancer, where it functions as an oncogene 564. High SNRPD2 expression associates with poor prognosis and cancer-selective lethality, making it an attractive therapeutic target 6. In hepatocellular carcinoma, SNRPD2 drives a positive feedback loop with MYC through DDX39A splicing regulation 5. In heart failure, SNRPD2 is upregulated in ischemic cardiomyopathy and correlates with left ventricular mass index 7. Additionally, SNRPD2 serves as a potential biomarker for predicting cognitive decline in Alzheimer's disease progression 8.