PTBP1

PTBP1
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1QM9, 1SJQ, 1SJR, 2AD9, 2ADB, 2ADC, 2EVZ, 3ZZY, 3ZZZ
Identifiers
Aliases	PTBP1, HNRNP-I, HNRNPI, HNRPI, PTB, PTB-1, PTB-T, PTB2, PTB3, PTB4, pPTB, polypyrimidine tract binding protein 1
External IDs	MGI: 97791 HomoloGene: 49188 GeneCards: PTBP1
Gene ontology Molecular function • nucleotide binding • pre-mRNA binding • poly(A) RNA binding • protein binding • poly-pyrimidine tract binding • RNA binding • nucleic acid binding Cellular component • nucleolus • extracellular exosome • membrane • nucleus • nucleoplasm Biological process • mRNA splicing, via spliceosome • mRNA processing • negative regulation of mRNA splicing, via spliceosome • gene expression • regulation of alternative mRNA splicing, via spliceosome • negative regulation of RNA splicing • RNA splicing • negative regulation of muscle cell differentiation • alternative mRNA splicing, via spliceosome • fibroblast growth factor receptor signaling pathway • IRES-dependent viral translational initiation Sources:Amigo / QuickGO
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	5725	19205
Ensembl	ENSG00000011304	ENSMUSG00000006498
UniProt	P26599	P17225
RefSeq (mRNA)	NM_002819 NM_031990 NM_031991 NM_175847	NM_001077363 NM_001283013 NM_008956
RefSeq (protein)	NP_002810.1 NP_114367.1 NP_114368.1	n/a
Location (UCSC)	Chr 19: 0.8 – 0.81 Mb	Chr 10: 79.85 – 79.86 Mb
PubMed search	[1]	[2]
Wikidata

Polypyrimidine tract-binding protein 1 is a protein that in humans is encoded by the PTBP1 gene.^[3][4][5]

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.^[5]

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.^[6]

Interactions

PTBP1 has been shown to interact with HNRPK,^[7] PCBP2,^[7] SFPQ^[8][9] and HNRNPL.^[7][10]

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.^[11]

References

Further reading

PDB gallery
1qm9: NMR, REPRESENTATIVE STRUCTURE  1sjq: NMR Structure of RRM1 from Human Polypyrimidine Tract Binding Protein Isoform 1 (PTB1)  1sjr: NMR Structure of RRM2 from Human Polypyrimidine Tract Binding Protein Isoform 1 (PTB1)  2ad9: Solution structure of Polypyrimidine Tract Binding protein RBD1 complexed with CUCUCU RNA  2adb: Solution structure of Polypyrimidine Tract Binding protein RBD2 complexed with CUCUCU RNA  2adc: Solution structure of Polypyrimidine Tract Binding protein RBD34 complexed with CUCUCU RNA  2evz: Structure of RNA Binding Domains 3 and 4 of Polypyrimidine Tract Binding Protein