The function of SARNP (SAP domain containing ribonucleoprotein, Ensembl gene identifier ENSG00000205323) is as follows. Binds both single-stranded and double-stranded DNA with higher affinity for the single-stranded form. Specifically binds to scaffold/matrix attachment region DNA. Also binds single-stranded RNA. Enhances RNA unwinding activity of DDX39A. May participate in important transcriptional or translational control of cell growth, metabolism and carcinogenesis. Component of the TREX complex which is thought to couple mRNA transcription, processing and nuclear export, and specifically associates with spliced mRNA and not with unspliced pre- mRNA (PubMed:15338056, PubMed:17196963, PubMed:20844015). The TREX complex is recruited to spliced mRNAs by a transcription-independent mechanism, binds to mRNA upstream of the exon-junction complex (EJC) and is recruited in a splicing- and cap-dependent manner to a region near the 5' end of the mRNA where it functions in mRNA export to the cytoplasm via the TAP/NXF1 pathway (PubMed:15338056, PubMed:17196963, PubMed:20844015). Associates with DDX39B, which facilitates RNA binding of DDX39B and likely plays a role in mRNA export (PubMed:37578863). {ECO:0000269|PubMed:15338056, ECO:0000269|PubMed:17196963, ECO:0000269|PubMed:20844015, ECO:0000269|PubMed:37578863}.