PTBP1 (polypyrimidine tract binding protein 1) is a crucial RNA-binding protein that regulates pre-mRNA splicing and alternative splicing events. PTBP1 binds to polypyrimidine tracts in introns and promotes RNA looping to control exon inclusion or skipping 1. The protein exhibits positional rules in splicing regulation, where PTBP1-associated loops within individual introns promote cassette exon splicing, while loops spanning across cassette exons repress splicing 1. PTBP1 directly binds to and promotes alternative splicing that leads to nonsense-mediated mRNA decay, as demonstrated with SYNGAP1 regulation 2. Beyond splicing control, PTBP1 depletion can convert astrocytes to functional neurons both in vitro and in vivo, showing therapeutic potential for neurodegenerative diseases like Parkinson's disease 3. However, some astrocyte-to-neuron conversion studies have been challenged by lineage tracing experiments 4. In cancer contexts, PTBP1 knockdown promotes neural differentiation of glioblastoma cells through UNC5B receptor signaling, inhibiting tumor growth 5. PTBP1 is also subject to post-translational modifications, with lactylation at K436 enhancing its RNA-binding capacity and promoting glioma stem cell maintenance through metabolic reprogramming 6. These findings establish PTBP1 as a critical regulator of RNA processing with significant implications for neurological diseases and cancer therapy.