NCBP1 (nuclear cap binding protein subunit 1) is an essential component of the nuclear cap-binding complex (CBC) that binds to the 5'-methylguanosine cap of RNA polymerase II transcripts 1. NCBP1 is required for cell viability and functions in mRNA export by forming complexes with either NCBP2 (conventional CBC) or NCBP3 (alternative CBC) 2. The CBC-ALYREF structure reveals that NCBP1 directly contacts ALYREF to facilitate mRNA export through recruitment of the TREX complex 1. NCBP1 works with NCBP3 to interact with Exon Junction Complex and TREX components, supporting mRNA biogenesis and nuclear export of polyadenylated RNAs 3. Disease relevance includes significant overexpression in multiple cancers: NCBP1 promotes lung adenocarcinoma progression through CUL4B upregulation 4, enhances diffuse large B-cell lymphoma proliferation via METTL3-mediated m6A modification of c-Myc 5, and serves as a prognostic biomarker in breast cancer and sarcoma 67. NCBP1 also participates in meiotic silencing mechanisms in fungi through interaction with RNAi machinery 8. Clinically, NCBP1 represents a potential therapeutic target due to its essential role in mRNA metabolism and oncogenic functions across various cancer types.