PTBP1

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. This gene belongs to the subfamily of ubiquitously expressed heterogeneous nuclear ribonucleoproteins (hnRNPs). The hnRNPs are RNA-binding proteins and they complex with heterogeneous nuclear RNA (hnRNA). These proteins are associated with pre-mRNAs in the nucleus and appear to influence pre-mRNA processing and other aspects of mRNA metabolism and transport. While all of the hnRNPs are present in the nucleus, some seem to shuttle between the nucleus and the cytoplasm. The hnRNP proteins have distinct nucleic acid binding properties. The protein encoded by this gene has four repeats of quasi-RNA recognition motif (RRM) domains that bind RNAs. This protein binds to the intronic polypyrimidine tracts that requires pre-mRNA splicing and acts via the protein degradation ubiquitin-proteasome pathway. It may also promote the binding of U2 snRNP to pre-mRNAs. This protein is localized in the nucleoplasm and it is also detected in the perinucleolar structure. Alternatively spliced transcript variants encoding different isoforms have been described

PTBP1; polypyrimidine tract binding protein 1; polypyrimidine tract binding protein (heterogeneous nuclear ribonucleoprotein I) , PTB; polypyrimidine tract-binding protein 1; heterogeneous nuclear ribonucleoprotein I; HNRNP I; HNRPI; pPTB; PTB 1; PTB2; PT;