Polypyrimidine tract-binding protein Tags: Protein.Polypyrimidine tract-binding protein is an RNA-binding protein also known as PTB or hnRNP I. PTB functions mainly as a splicing regulator although it is also involved in alternative 3′ end processing mRNA stability and RNA localization. arm p band 21.3, 13.3 chromosome 19, 1 EntrezGene 5725, 58155 HGNCid 9583, 17662 locus supplementary data -22.1 OMIM id 600693, 608449 RefSeq NM_002819, NM_021190 symbol PTB, PTBP1, PTBP2 UniProt P26599, Q9UKA9 Learn more... Loading...