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Gene Review

PTBP1  -  polypyrimidine tract binding protein 1

Homo sapiens

Synonyms: 57 kDa RNA-binding protein PPTB-1, HNRNP-I, HNRNPI, HNRPI, Heterogeneous nuclear ribonucleoprotein I, ...
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Disease relevance of PTBP1


High impact information on PTBP1

  • Prior to this work, C2 domains were thought to bind only to phospholipids or to unphosphorylated proteins, and the SH2 and PTB domains were the only signaling domains known to recognize phosphotyrosine [6].
  • In eukaryotic cells, the SH2 and PTB domains mediate protein-protein interactions by recognizing phosphotyrosine residues on target proteins [7].
  • Here it is shown that PTB can regulate alternative splicing by selectively repressing 3' splice sites that contain a PTB-binding site [8].
  • These proteins repress certain exons in early myoblasts, but upon differentiation of mature myotubes PTB/nPTB expression is reduced, leading to increased inclusion of their target exons [9].
  • During differentiation of C2C12 myoblasts, nPTB protein but not mRNA expression is strongly reduced, concurrent with the up-regulation of miR-133 and the induction of splicing for several PTB-repressed exons [9].

Chemical compound and disease context of PTBP1


Biological context of PTBP1


Anatomical context of PTBP1

  • The Apaf-1 internal ribosome entry segment attains the correct structural conformation for function via interactions with PTB and unr [18].
  • PKA directly phosphorylates PTB on conserved Ser-16, and PKA activation in PC12 cells induces Ser-16 phosphorylation [17].
  • Similarly, in Xenopus oocytes, the phospho-Ser-16-PTB is restricted to the cytoplasm, whereas the non-Ser-16-phosphorylated PTB is nuclear [17].
  • To directly demonstrate the biological significance of Complex I binding to the CD154 transcript, cytoplasm from human Jurkat cells was fractionated over a sucrose gradient and the different cellular fractions subjected to immunoprecipitation with anti-PTB and anti-nucleolin Abs [19].
  • The N-terminal part of PTB is responsible for the enhancement of RNA binding by HeLa cell cytoplasmic factor(s) [20].

Associations of PTBP1 with chemical compounds

  • PTB carrying a Ser-16 to alanine mutation accumulates normally in the nucleus [17].
  • The Polypyrimidine Tract-binding Protein (PTB) Is Involved in the Post-transcriptional Regulation of Human Inducible Nitric Oxide Synthase Expression [21].
  • Mutation of the PTB-binding site significantly reduces the efficiency of the C2 poly(A) site both in vivo and in vitro [22].
  • Furthermore, analysis of the sequence requirement for targeting PTB to the PNC using a series of deletion mutants of the GFP-PTB fusion protein showed that at least three RRMs at either the COOH or NH2 terminus are required for the fusion protein to be targeted to the PNC [23].
  • This may be analogous to its role in alternative splicing, where PTB competes with U2AF for binding to pyrimidine-rich intronic sequences [24].

Physical interactions of PTBP1


Regulatory relationships of PTBP1


Other interactions of PTBP1

  • The interactions of PTB-1 and PCBP1 with their cognate binding sites on the IRES disrupt many of the RNA-RNA interactions, and this creates a largely unstructured region of approximately 40 nucleotides that could permit ribosome binding [32].
  • Isolated nuclear matrices contained the bulk of PSF, but only minor amounts of PTB [33].
  • Sequence comparisons indicate that pPTB is distantly related to the hnRNP L protein and that these two proteins should be considered as members of a novel family of RNA-binding proteins [15].
  • Role of La autoantigen and polypyrimidine tract-binding protein in HCV replication [34].
  • Three proteins were identified in the cofactor fraction including two previously described proteins, elongation factor 1alpha (EF-1alpha) and the polypyrimidine tract-binding protein (PTB), and a novel protein designated the stimulator of TAR RNA-binding proteins (SRB) [35].

Analytical, diagnostic and therapeutic context of PTBP1


  1. Hepatitis C virus internal ribosome entry site-dependent translation in Saccharomyces cerevisiae is independent of polypyrimidine tract-binding protein, poly(rC)-binding protein 2, and La protein. Rosenfeld, A.B., Racaniello, V.R. J. Virol. (2005) [Pubmed]
  2. Translation of polioviral mRNA is inhibited by cleavage of polypyrimidine tract-binding proteins executed by polioviral 3C(pro). Back, S.H., Kim, Y.K., Kim, W.J., Cho, S., Oh, H.R., Kim, J.E., Jang, S.K. J. Virol. (2002) [Pubmed]
  3. Polypyrimidine tract binding protein and Notch1 are independently re-expressed in glioma. Cheung, H.C., Corley, L.J., Fuller, G.N., McCutcheon, I.E., Cote, G.J. Mod. Pathol. (2006) [Pubmed]
  4. Expression of the splicing regulator polypyrimidine tract-binding protein in normal and neoplastic brain. McCutcheon, I.E., Hentschel, S.J., Fuller, G.N., Jin, W., Cote, G.J. Neuro-oncology (2004) [Pubmed]
  5. Role of polypyrimidine tract binding protein in the function of the hepatitis B virus posttranscriptional regulatory element. Zang, W.Q., Li, B., Huang, P.Y., Lai, M.M., Yen, T.S. J. Virol. (2001) [Pubmed]
  6. C2 can do it, too. Sondermann, H., Kuriyan, J. Cell (2005) [Pubmed]
  7. The C2 domain of PKCdelta is a phosphotyrosine binding domain. Benes, C.H., Wu, N., Elia, A.E., Dharia, T., Cantley, L.C., Soltoff, S.P. Cell (2005) [Pubmed]
  8. Distinct binding specificities and functions of higher eukaryotic polypyrimidine tract-binding proteins. Singh, R., Valcárcel, J., Green, M.R. Science (1995) [Pubmed]
  9. MicroRNAs regulate the expression of the alternative splicing factor nPTB during muscle development. Boutz, P.L., Chawla, G., Stoilov, P., Black, D.L. Genes Dev. (2007) [Pubmed]
  10. Alternative splicing of the multidrug resistance protein 1/ATP binding cassette transporter subfamily gene in ovarian cancer creates functional splice variants and is associated with increased expression of the splicing factors PTB and SRp20. He, X., Ee, P.L., Coon, J.S., Beck, W.T. Clin. Cancer Res. (2004) [Pubmed]
  11. T cell activation, apoptosis and cytokine dysregulation in the (co)pathogenesis of HIV and pulmonary tuberculosis (TB). Hertoghe, T., Wajja, A., Ntambi, L., Okwera, A., Aziz, M.A., Hirsch, C., Johnson, J., Toossi, Z., Mugerwa, R., Mugyenyi, P., Colebunders, R., Ellner, J., Vanham, G. Clin. Exp. Immunol. (2000) [Pubmed]
  12. Contact dermatitis from PTBP resin and tricresyl ethyl phthalate in a plastic nail adhesive. Burrows, D., Rycroft, R.J. Contact Derm. (1981) [Pubmed]
  13. Occupational eczema from para-tertiary-butylphenol formaldehyde resins: a review of the sensitizing resins. Foussereau, J., Cavelier, C., Selig, D. Contact Derm. (1976) [Pubmed]
  14. Characterization of the molecular mechanisms involved in the increased insulin secretion in rats with acute liver failure. Kuwahata, M., Tomoe, Y., Harada, N., Amano, S., Segawa, H., Tatsumi, S., Ito, M., Oka, T., Miyamoto, K. Biochim. Biophys. Acta (2007) [Pubmed]
  15. Characterization of cDNAs encoding the polypyrimidine tract-binding protein. Gil, A., Sharp, P.A., Jamison, S.F., Garcia-Blanco, M.A. Genes Dev. (1991) [Pubmed]
  16. Polypyrimidine tract binding protein regulates IRES-mediated gene expression during apoptosis. Bushell, M., Stoneley, M., Kong, Y.W., Hamilton, T.L., Spriggs, K.A., Dobbyn, H.C., Qin, X., Sarnow, P., Willis, A.E. Mol. Cell (2006) [Pubmed]
  17. Protein kinase A phosphorylation modulates transport of the polypyrimidine tract-binding protein. Xie, J., Lee, J.A., Kress, T.L., Mowry, K.L., Black, D.L. Proc. Natl. Acad. Sci. U.S.A. (2003) [Pubmed]
  18. The Apaf-1 internal ribosome entry segment attains the correct structural conformation for function via interactions with PTB and unr. Mitchell, S.A., Spriggs, K.A., Coldwell, M.J., Jackson, R.J., Willis, A.E. Mol. Cell (2003) [Pubmed]
  19. Nucleolin is a second component of the CD154 mRNA stability complex that regulates mRNA turnover in activated T cells. Singh, K., Laughlin, J., Kosinski, P.A., Covey, L.R. J. Immunol. (2004) [Pubmed]
  20. Determination of functional domains in polypyrimidine-tract-binding protein. Oh, Y.L., Hahm, B., Kim, Y.K., Lee, H.K., Lee, J.W., Song, O., Tsukiyama-Kohara, K., Kohara, M., Nomoto, A., Jang, S.K. Biochem. J. (1998) [Pubmed]
  21. The Polypyrimidine Tract-binding Protein (PTB) Is Involved in the Post-transcriptional Regulation of Human Inducible Nitric Oxide Synthase Expression. Pautz, A., Linker, K., Hubrich, T., Korhonen, R., Altenh??fer, S., Kleinert, H. J. Biol. Chem. (2006) [Pubmed]
  22. The upstream sequence element of the C2 complement poly(A) signal activates mRNA 3' end formation by two distinct mechanisms. Moreira, A., Takagaki, Y., Brackenridge, S., Wollerton, M., Manley, J.L., Proudfoot, N.J. Genes Dev. (1998) [Pubmed]
  23. The dynamic organization of the perinucleolar compartment in the cell nucleus. Huang, S., Deerinck, T.J., Ellisman, M.H., Spector, D.L. J. Cell Biol. (1997) [Pubmed]
  24. Polypyrimidine tract binding protein modulates efficiency of polyadenylation. Castelo-Branco, P., Furger, A., Wollerton, M., Smith, C., Moreira, A., Proudfoot, N. Mol. Cell. Biol. (2004) [Pubmed]
  25. Polypyrimidine tract binding protein and poly r(C) binding protein 1 interact with the BAG-1 IRES and stimulate its activity in vitro and in vivo. Pickering, B.M., Mitchell, S.A., Evans, J.R., Willis, A.E. Nucleic Acids Res. (2003) [Pubmed]
  26. The polypyrimidine tract binding protein binds upstream of neural cell-specific c-src exon N1 to repress the splicing of the intron downstream. Chan, R.C., Black, D.L. Mol. Cell. Biol. (1997) [Pubmed]
  27. The Polypyrimidine Tract Binding Protein (PTB) Represses Splicing of Exon 6B from the {beta}-Tropomyosin Pre-mRNA by Directly Interfering with the Binding of the U2AF65 Subunit. Sauli??re, J., Sureau, A., Expert-Bezan??on, A., Marie, J. Mol. Cell. Biol. (2006) [Pubmed]
  28. A complex containing polypyrimidine tract-binding protein is involved in regulating the stability of CD40 ligand (CD154) mRNA. Kosinski, P.A., Laughlin, J., Singh, K., Covey, L.R. J. Immunol. (2003) [Pubmed]
  29. Role of an inhibitory pyrimidine element and polypyrimidine tract binding protein in repression of a regulated alpha-tropomyosin exon. Gooding, C., Roberts, G.C., Smith, C.W. RNA (1998) [Pubmed]
  30. Multisite RNA binding and release of polypyrimidine tract binding protein during the regulation of c-src neural-specific splicing. Chou, M.Y., Underwood, J.G., Nikolic, J., Luu, M.H., Black, D.L. Mol. Cell (2000) [Pubmed]
  31. Regulation of Fas alternative splicing by antagonistic effects of TIA-1 and PTB on exon definition. Izquierdo, J.M., Majós, N., Bonnal, S., Martínez, C., Castelo, R., Guigó, R., Bilbao, D., Valcárcel, J. Mol. Cell (2005) [Pubmed]
  32. Bag-1 internal ribosome entry segment activity is promoted by structural changes mediated by poly(rC) binding protein 1 and recruitment of polypyrimidine tract binding protein 1. Pickering, B.M., Mitchell, S.A., Spriggs, K.A., Stoneley, M., Willis, A.E. Mol. Cell. Biol. (2004) [Pubmed]
  33. Differential nuclear localization and nuclear matrix association of the splicing factors PSF and PTB. Meissner, M., Dechat, T., Gerner, C., Grimm, R., Foisner, R., Sauermann, G. J. Cell. Biochem. (2000) [Pubmed]
  34. Role of La autoantigen and polypyrimidine tract-binding protein in HCV replication. Domitrovich, A.M., Diebel, K.W., Ali, N., Sarker, S., Siddiqui, A. Virology (2005) [Pubmed]
  35. Identification of a group of cellular cofactors that stimulate the binding of RNA polymerase II and TRP-185 to human immunodeficiency virus 1 TAR RNA. Wu-Baer, F., Lane, W.S., Gaynor, R.B. J. Biol. Chem. (1996) [Pubmed]
  36. Molecular cloning and characterization of a new neuron-specific homologue of rat polypyrimidine tract binding protein. Kikuchi, T., Ichikawa, M., Arai, J., Tateiwa, H., Fu, L., Higuchi, K., Yoshimura, N. J. Biochem. (2000) [Pubmed]
  37. Structure of the two most C-terminal RNA recognition motifs of PTB using segmental isotope labeling. Vitali, F., Henning, A., Oberstrass, F.C., Hargous, Y., Auweter, S.D., Erat, M., Allain, F.H. EMBO J. (2006) [Pubmed]
  38. The polypyrimidine tract binding protein is a monomer. Monie, T.P., Hernandez, H., Robinson, C.V., Simpson, P., Matthews, S., Curry, S. RNA (2005) [Pubmed]
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