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Gene Review

PAB1  -  polyadenylate-binding protein

Saccharomyces cerevisiae S288c

Synonyms: ARS consensus-binding protein ACBP-67, PABP, Poly(A)-binding protein, Polyadenylate tail-binding protein, Polyadenylate-binding protein, cytoplasmic and nuclear, ...
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Disease relevance of PAB1

  • A nonspecific single-stranded binding protein from Escherichia coli did not restore stability to polyadenylated mRNA, and the stabilizing effect of PABP was inhibited by anti-PABP antibody [1].
  • Plants that accumulate the Pab1p display a range of abnormalities, ranging from a characteristic chlorosis in leaves to a necrosis and large inhibition of growth [2].

High impact information on PAB1


Biological context of PAB1

  • Deletion of the PAT1 gene affects translation initiation and suppresses a PAB1 gene deletion in yeast [7].
  • Second, overexpression of PAB1 does not cure the [PSI(+)] phenotype or solubilize detectable amounts of eRF3 [8].
  • Previous studies have implicated the cytoplasmic poly(A) tail-binding protein Pab1p in poly(A) tail length control during polyadenylation [9].
  • Here, we identify Nab2p as a nuclear poly(A)-binding protein required for both poly(A) tail length control and nuclear export of mRNA [9].
  • The suppression of pab1Delta by pbp1Delta appears to be different from that mediated by other pab1 suppressors, since disruption of PBP1 does not alter translation rates, affect accumulation of ribosomal subunits, change mRNA poly(A) tail lengths, or result in a defect in mRNA decay [10].

Anatomical context of PAB1

  • We determined that a fraction of Pbp1p cosediments with polysomes in sucrose gradients and that its distribution is very similar to that of Pab1p [10].
  • The yeast hsp70 homologue Ssa is required for translation and interacts with Sis1 and Pab1 on translating ribosomes [11].
  • Pab1p was found to associate with purified COPI-coated vesicles generated from Golgi membranes in vitro [12].
  • Furthermore, substituting PAB3 for the yeast Pab1p caused synthetic lethality with rna15-2 and gle2-1, alleles of the genes that encode a component of the nuclear pre-mRNA cleavage factor I, and a factor associated with the nuclear pore complex, respectively [13].
  • In this report, we have analyzed the effects of overexpressing PABP on the regulation of mRNAs during Xenopus oocyte maturation [14].

Associations of PAB1 with chemical compounds

  • Yeast mRNA Poly(A) tail length control can be reconstituted in vitro in the absence of Pab1p-dependent Poly(A) nuclease activity [15].
  • Yeast pab1 mutants were found to be sensitive to elevated concentrations of copper (Cu) and 3-aminotriazole (3-AT) in the growth medium [16].
  • This is 50 times more than required to bind all the poly(A) in the egg based on the binding stoichiometry of 1 PABP per 27 adenosine residues [17].
  • Both poly(A)(+) transcripts and/or Pab1p can be detected in P-bodies during glucose deprivation and in stationary phase [18].

Physical interactions of PAB1

  • Rbp29p can be co-immunoprecipitated with the poly(A) tail-binding protein Pab1p from crude yeast extracts in a dosage- and RNA-dependent manner [19].
  • We suggest a model in which these three factors and Ufd1p are part of a regulatory complex that exploits Pab1p to link cleavage and polyadenylation factors of CFIA and CFIB (cleavage factors IA and IB) to the polyadenylation factors of CPF (cleavage and polyadenylation factor) [20].
  • These data suggest that eIF4G mediates poly(A) tail stimulated translation in vitro, and that Pab1p and the domain encompassing the Pab1p-binding site on eIF4G can compensate for partial loss of eIF4E function in vivo [21].
  • However, the domains required for Pan3p and Pbp1p binding on Pab1p are distinct [22].
  • Yeast Pab1 interacts with Rna15 and participates in the control of the poly(A) tail length in vitro [23].

Regulatory relationships of PAB1

  • These effects suggest that Pbp1p may act to repress the ability of Pab1p to negatively regulate polyadenylation [10].
  • Furthermore, the inviability of a pab1 deletion strain is suppressed by a mutation in the 5'-3' exoribonuclease RRP6, a component of the nuclear exosome [24].
  • We confirmed that a genetic interaction exists between eRF3 and Pab1p and showed that Pab1p overexpression enhances the efficiency of termination in SUP35 (eRF3) mutant and [PSI(+)] cells [8].
  • This suggests that serum stimulates the interaction between eIF4G and PABP by a distinct mechanism that is independent of both the mTOR pathway and the enhanced association of eIF4G with eIF4E [25].

Other interactions of PAB1

  • Disruption of PBP1 showed that it is not essential for viability but can suppress the lethality associated with a PAB1 deletion [10].
  • The yeast Pan2 protein is required for poly(A)-binding protein-stimulated poly(A)-nuclease activity [26].
  • Pab1 shuttles rapidly between the nucleus and the cytoplasm and partially accumulates in the nucleus when the function of Xpo1/Crm1 is inhibited [24].
  • RNase mapping of transcripts from pap1-1 cells revealed PAB1 mRNA to be poly(A)- whereas TCM1 exists as equal amounts of poly(A)- and poly(A)+ mRNA 60 min after shift [27].
  • These data confirm that Pan2p and not Pan1p is required for PAN activity, and they suggest that ribonucleases other than the Pab1p-stimulated PAN are capable of shortening poly(A) tails in vivo [26].

Analytical, diagnostic and therapeutic context of PAB1


  1. The poly(A)-poly(A)-binding protein complex is a major determinant of mRNA stability in vitro. Bernstein, P., Peltz, S.W., Ross, J. Mol. Cell. Biol. (1989) [Pubmed]
  2. The yeast polyadenylate-binding protein (PAB1) gene acts as a disease lesion mimic gene when expressed in plants. Li, Q., Von Lanken, C., Yang, J., Lawrence, C.B., Hunt, A.G. Plant Mol. Biol. (2000) [Pubmed]
  3. A single gene from yeast for both nuclear and cytoplasmic polyadenylate-binding proteins: domain structure and expression. Sachs, A.B., Bond, M.W., Kornberg, R.D. Cell (1986) [Pubmed]
  4. Translation initiation and ribosomal biogenesis: involvement of a putative rRNA helicase and RPL46. Sachs, A.B., Davis, R.W. Science (1990) [Pubmed]
  5. Yeast poly(A)-binding protein, Pab1, and PAN, a poly(A) nuclease complex recruited by Pab1, connect mRNA biogenesis to export. Dunn, E.F., Hammell, C.M., Hodge, C.A., Cole, C.N. Genes Dev. (2005) [Pubmed]
  6. mRNA stabilization by poly(A) binding protein is independent of poly(A) and requires translation. Coller, J.M., Gray, N.K., Wickens, M.P. Genes Dev. (1998) [Pubmed]
  7. Deletion of the PAT1 gene affects translation initiation and suppresses a PAB1 gene deletion in yeast. Wyers, F., Minet, M., Dufour, M.E., Vo, L.T., Lacroute, F. Mol. Cell. Biol. (2000) [Pubmed]
  8. Poly(A)-binding protein acts in translation termination via eukaryotic release factor 3 interaction and does not influence [PSI(+)] propagation. Cosson, B., Couturier, A., Chabelskaya, S., Kiktev, D., Inge-Vechtomov, S., Philippe, M., Zhouravleva, G. Mol. Cell. Biol. (2002) [Pubmed]
  9. Dual requirement for yeast hnRNP Nab2p in mRNA poly(A) tail length control and nuclear export. Hector, R.E., Nykamp, K.R., Dheur, S., Anderson, J.T., Non, P.J., Urbinati, C.R., Wilson, S.M., Minvielle-Sebastia, L., Swanson, M.S. EMBO J. (2002) [Pubmed]
  10. Pbp1p, a factor interacting with Saccharomyces cerevisiae poly(A)-binding protein, regulates polyadenylation. Mangus, D.A., Amrani, N., Jacobson, A. Mol. Cell. Biol. (1998) [Pubmed]
  11. The yeast hsp70 homologue Ssa is required for translation and interacts with Sis1 and Pab1 on translating ribosomes. Horton, L.E., James, P., Craig, E.A., Hensold, J.O. J. Biol. Chem. (2001) [Pubmed]
  12. Arf1p provides an unexpected link between COPI vesicles and mRNA in Saccharomyces cerevisiae. Trautwein, M., Dengjel, J., Schirle, M., Spang, A. Mol. Biol. Cell (2004) [Pubmed]
  13. Evidence that poly(A) binding protein has an evolutionarily conserved function in facilitating mRNA biogenesis and export. Chekanova, J.A., Belostotsky, D.A. RNA (2003) [Pubmed]
  14. Overexpression of poly(A) binding protein prevents maturation-specific deadenylation and translational inactivation in Xenopus oocytes. Wormington, M., Searfoss, A.M., Hurney, C.A. EMBO J. (1996) [Pubmed]
  15. Yeast mRNA Poly(A) tail length control can be reconstituted in vitro in the absence of Pab1p-dependent Poly(A) nuclease activity. Dheur, S., Nykamp, K.R., Viphakone, N., Swanson, M.S., Minvielle-Sebastia, L. J. Biol. Chem. (2005) [Pubmed]
  16. Decapping of stabilized, polyadenylated mRNA in yeast pab1 mutants. Morrissey, J.P., Deardorff, J.A., Hebron, C., Sachs, A.B. Yeast (1999) [Pubmed]
  17. Identification and characterization of the poly(A)-binding proteins from the sea urchin: a quantitative analysis. Drawbridge, J., Grainger, J.L., Winkler, M.M. Mol. Cell. Biol. (1990) [Pubmed]
  18. Accumulation of polyadenylated mRNA, Pab1p, eIF4E, and eIF4G with P-bodies in Saccharomyces cerevisiae. Brengues, M., Parker, R. Mol. Biol. Cell (2007) [Pubmed]
  19. The Saccharomyces cerevisiae RNA-binding protein Rbp29 functions in cytoplasmic mRNA metabolism. Winstall, E., Sadowski, M., Kuhn, U., Wahle, E., Sachs, A.B. J. Biol. Chem. (2000) [Pubmed]
  20. Identification of factors regulating poly(A) tail synthesis and maturation. Mangus, D.A., Smith, M.M., McSweeney, J.M., Jacobson, A. Mol. Cell. Biol. (2004) [Pubmed]
  21. Translation initiation factor eIF4G mediates in vitro poly(A) tail-dependent translation. Tarun, S.Z., Wells, S.E., Deardorff, J.A., Sachs, A.B. Proc. Natl. Acad. Sci. U.S.A. (1997) [Pubmed]
  22. Positive and negative regulation of poly(A) nuclease. Mangus, D.A., Evans, M.C., Agrin, N.S., Smith, M., Gongidi, P., Jacobson, A. Mol. Cell. Biol. (2004) [Pubmed]
  23. Yeast Pab1 interacts with Rna15 and participates in the control of the poly(A) tail length in vitro. Amrani, N., Minet, M., Le Gouar, M., Lacroute, F., Wyers, F. Mol. Cell. Biol. (1997) [Pubmed]
  24. Yeast poly(A)-binding protein Pab1 shuttles between the nucleus and the cytoplasm and functions in mRNA export. Brune, C., Munchel, S.E., Fischer, N., Podtelejnikov, A.V., Weis, K. RNA (2005) [Pubmed]
  25. The association of initiation factor 4F with poly(A)-binding protein is enhanced in serum-stimulated Xenopus kidney cells. Fraser, C.S., Pain, V.M., Morley, S.J. J. Biol. Chem. (1999) [Pubmed]
  26. The yeast Pan2 protein is required for poly(A)-binding protein-stimulated poly(A)-nuclease activity. Boeck, R., Tarun, S., Rieger, M., Deardorff, J.A., Müller-Auer, S., Sachs, A.B. J. Biol. Chem. (1996) [Pubmed]
  27. Efficient translation of poly(A)-deficient mRNAs in Saccharomyces cerevisiae. Proweller, A., Butler, S. Genes Dev. (1994) [Pubmed]
  28. PUB1 is a major nuclear and cytoplasmic polyadenylated RNA-binding protein in Saccharomyces cerevisiae. Anderson, J.T., Paddy, M.R., Swanson, M.S. Mol. Cell. Biol. (1993) [Pubmed]
  29. Differential organ-specific expression of three poly(A)-binding-protein genes from Arabidopsis thaliana. Belostotsky, D.A., Meagher, R.B. Proc. Natl. Acad. Sci. U.S.A. (1993) [Pubmed]
  30. Circularization of mRNA by eukaryotic translation initiation factors. Wells, S.E., Hillner, P.E., Vale, R.D., Sachs, A.B. Mol. Cell (1998) [Pubmed]
  31. A conditional yeast mutant deficient in mRNA transport from nucleus to cytoplasm. Kadowaki, T., Zhao, Y., Tartakoff, A.M. Proc. Natl. Acad. Sci. U.S.A. (1992) [Pubmed]
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