PTBP1

Polypyrimidine tract binding protein 1
250px PDB rendering based on 1qm9.
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 1QM9, 1SJQ, 1SJR, 2AD9, 2ADB, 2ADC, 2EVZ, 3ZZY, 3ZZZ
Identifiers
Symbols	PTBP1 ; HNRNP-I; HNRNPI; HNRPI; PTB; PTB-1; PTB-T; PTB2; PTB3; PTB4; pPTB
External IDs	OMIM: 600693 MGI: 97791 HomoloGene: 49188 ChEMBL: 1293230 GeneCards: PTBP1 Gene
Gene ontology Molecular function • nucleotide binding • RNA binding • protein binding • poly-pyrimidine tract binding • pre-mRNA binding • poly(A) RNA binding Cellular component • nucleoplasm • nucleolus • membrane • extracellular exosome Biological process • alternative mRNA splicing, via spliceosome • regulation of alternative mRNA splicing, via spliceosome • mRNA splicing, via spliceosome • mRNA processing • RNA splicing • gene expression • negative regulation of RNA splicing • positive regulation of transcription from RNA polymerase II promoter • negative regulation of mRNA splicing, via spliceosome • negative regulation of muscle cell differentiation Sources: Amigo / QuickGO
RNA expression pattern
File:PBB GE PTBP1 212016 s at tn.png
File:PBB GE PTBP1 202189 x at tn.png
File:PBB GE PTBP1 211270 x at tn.png
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	5725	19205
Ensembl	ENSG00000011304	ENSMUSG00000006498
UniProt	P26599	Q8BGJ5
RefSeq (mRNA)	NM_002819	NM_001077363
RefSeq (protein)	NP_002810	NP_001070831
Location (UCSC)	Chr 19: 0.8 – 0.81 Mb	Chr 10: 79.85 – 79.86 Mb
PubMed search	[1]	[2]

Polypyrimidine tract-binding protein 1 is a protein that in humans is encoded by the PTBP1 gene.

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 In Mammals

In brains of mammals, transcripts from the PTBP1 gene are missing one exon (exon 9) that is included in the brains of other vertebrates, as a result of alternative splicing. This contributes to the evolutionary difference between the nervous system of mammals and other vertebrates.

Interactions

PTBP1 has been shown to interact with HNRPK, PCBP2, SFPQ and HNRNPL.

This gene is targeted by the microRNA miR-124. During neuronal differentiation, miR-124 reduces PTBP1 levels, leading to the accumulation of correctly spliced PTBP2 mRNA and a dramatic increase in PTBP2 protein.