Polypyrimidine tract-binding protein 1 (UniProt P26599; also known as 57 kDa RNA-binding protein PPTB-1, Heterogeneous nuclear ribonucleoprotein I, Heterogeneous nuclear ribonucleoprotein polypeptide I, hnRNP I, PTB, RNA-binding protein) is encoded by the PTBP1 (also known as HNRNP-I, HNRNPI, HNRPI,...