SARNP (SAP domain containing ribonucleoprotein) is a nucleocytoplasmic RNA-binding protein that functions as a core component of the TREX (transcription-export) complex. Structurally, SARNP contains tandem DDX39B interacting motifs enabling formation of high-order multivalent complexes with the RNA helicase DDX39B, facilitating mRNA ribonucleoprotein (mRNP) assembly 1. SARNP binds both single-stranded and double-stranded DNA with higher affinity for single-stranded forms, and also binds RNA, enhancing DDX39B's RNA unwinding activity 2. Functionally, SARNP associates with spliced mRNA and participates in mRNA export from the nucleus via the TAP/NXF1 pathway, binding upstream of the exon-junction complex 3. Beyond nuclear export, SARNP regulates epithelial-mesenchymal transition by negatively regulating E-cadherin expression through interaction with pinin, thereby maintaining mesenchymal phenotype in breast cancer cells 3. Clinically, SARNP is implicated in multiple malignancies including triple-negative breast cancer, glioma, and rectal cancer, where it serves as a prognostic biomarker 45. SARNP is also associated with diverse ophthalmologic disorders including birdshot chorioretinopathy, cataracts, and familial exudative vitreoretinopathy. Its dysregulation in radioresistant glioblastoma suggests potential therapeutic targeting 6.