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Polyadenylate-binding protein 2
Known also as: Nuclear poly(A)-binding protein 1, Poly(A)-binding protein 2
Known abbreviations: PABP-2, OPMD, PAB2, PABII, PABP2, PABPN1
Yeast homolog: PAB2
Protein
Structures Models Domains Secondary structure Disorder |
This protein is highly disordered (73 % of residues are predicted to be disordered)
Top 3 models:
 |  |  |
| Template: 3pgw, chain S Method: hhsearch Fragment: 52-306 | Template: 2vod, chain B Method: compass Fragment: 22-155 | Template: 1h2t, chain Z Method: phyre Fragment: 143-283 |
This protein has alternative isoforms:
Isoform 1:
| Sequence length: | 306 aa |
| Molecular weight: | 32.749 kDa |
| Isoelectric point: | 4.89 |
1........10........20........30........40........50........60........70........80........90........100.......110.......120.......130
MAAAAAAAAAAGAAGGRGSGPGRRRHLVPGAGGEAGEGAPGGAGDYGNGLESEELEPEELLLEPEPEPEPEEEPPRPRAPPGAPGPGPGSGAPGSQEEEEEPGLVEGDPGDGAIEDPELEAIKARVREME
EEAEKLKELQNEVEKQMNMSPPPGNAGPVIMSIEEKMEADARSIYVGNVDYGATAEELEAHFHGCGSVNRVTILCDKFSGHPKGFAYIEFSDKESVRTSLALDESLFRGRQIKVIPKRTNRPGISTTDRG
FPRARYRARTTNYNSSRSRFYSGFNSRPRGRVYRGRARATSWYSPY
Isoform 2:
| Sequence length: | 296 aa |
| Molecular weight: | 31.497 kDa |
| Isoelectric point: | 4.78 |
1........10........20........30........40........50........60........70........80........90........100.......110.......120.......130
MAAAAAAAAAAGAAGGRGSGPGRRRHLVPGAGGEAGEGAPGGAGDYGNGLESEELEPEELLLEPEPEPEPEEEPPRPRAPPGAPGPGPGSGAPGSQEEEEEPGLVEGDPGDGAIEDPELEAIKARVREME
EEAEKLKELQNEVEKQMNMSPPPGNAGPVIMSIEEKMEADARSIYVGNVDYGATAEELEAHFHGCGSVNRVTILCDKFSGHPKGFAYIEFSDKESVRTSLALDESLFRGRQIKVIPKRTNRPGISTTDRG
FPRARYRARTTNYNSSRSRFYSGFNSRPRGRVYRSG
Isoform 3:
| Sequence length: | 333 aa |
| Molecular weight: | 37.171 kDa |
| Isoelectric point: | 8.08 |
1........10........20........30........40........50........60........70........80........90........100.......110.......120.......130
MATPASAPDTRALVADFVGYKLRQKGYVCGAGPGEGPAADPLHQAMRAAGDEFETRFRRTFSDLAAQLHVTPGSAQQRFTQVSDELFQGGPNWGRLVAFFVFGAALCAESVNKEMEPLVGQVQEWMVAYL
ETQLADWIHSSGGWELEAIKARVREMEEEAEKLKELQNEVEKQMNMSPPPGNAGPVIMSIEEKMEADARSIYVGNVDYGATAEELEAHFHGCGSVNRVTILCDKFSGHPKGFAYIEFSDKESVRTSLALD
ESLFRGRQIKVIPKRTNRPGISTTDRGFPRARYRARTTNYNSSRSRFYSGFNSRPRGRVYRGRARATSWYSPY
Gene location: 14q11.2
Summary
An abundant nuclear protein that binds with high affinity to nascent poly(A) tails. The protein is required for progressive and efficient polymerization of poly(A) tails at the 3' ends of eukaryotic transcripts and controls the size of the poly(A) tail to about 250 nt. At steady-state, this protein is localized in the nucleus whereas a different poly(A) binding protein is localized in the cytoplasm.
The gene contains a GCG trinucleotide repeat at the 5' end of the coding region, and expansion of this repeat from the normal 6 copies to 8-13 copies leads to autosomal dominant oculopharyngeal muscular dystrophy (OPMD) disease. Related pseudogenes have been identified on chromosomes 19 and X.
Involved in the 3'-end formation of mRNA precursors (pre-mRNA) by the addition of a poly(A) tail of 200-250 nt to the upstream cleavage product. Stimulates poly(A) polymerase (PAPOLA) conferring processivity on the poly(A) tail elongation reaction and controls also the poly(A) tail length. Increases the affinity of poly(A) polymerase for RNA. Is also present at various stages of mRNA metabolism including nucleocytoplasmic trafficking and nonsense-mediated decay (NMD) of mRNA. Cooperates with SKIP to synergistically activate E-box-mediated transcription through MYOD1 and may regulate the expression of muscle-specific genes. Binds to poly(A) and to poly(G) with high affinity. May protect the poly(A) tail from degradation.
Acts as monomer and homooligomer. Binds RNA as a monomer and oligomerizes when bound to poly(A). Interacts with PAPOLA, but only in presence of oligo(A) RNA. Interacts with transportin.
The association of the expanded polyalanine mutations together with the capability to oligomerize may induce these inclusions and cell death. Expanded polyalanine mutations may either result from unequal crossing over during germ cell homologous recombination or from DNA slippage. The pathogenic mechanisms mediated by polyalanine expansion mutations may be either a general disruption of cellular RNA metabolism due to the trapping by the inclusions of PABPN1, mRNAs and/or nuclear proteins, resulting in the induction of cell death; or may change the normal muscle cell differentiation.
See this protein in other databases:
Literature:
- Chen Z, Li Y, Krug RM et al. Influenza A virus NS1 protein targets poly(A)-binding protein II of the cellular 3"-end processing machinery. EMBO J 1999 18(8):2273-83, doi: 10.1093/emboj/18.8.2273, PMID: 10205180.
- Calado A, Kutay U, Kuhn U et al. Deciphering the cellular pathway for transport of poly(A)-binding protein II. RNA 2000 6(2):245-56, doi: , PMID: 10688363.
- Hosoda N, Lejeune F, Maquat LE et al. Evidence that poly(A) binding protein C1 binds nuclear pre-mRNA poly(A) tails. Mol Cell Biol 2006 26(8):3085-97, doi: 10.1128/MCB.26.8.3085-3097.2006, PMID: 16581783.
- Lemieux C, Bachand F. Cotranscriptional recruitment of the nuclear poly(A)-binding protein Pab2 to nascent transcripts and association with translating mRNPs. Nucleic Acids Res 2009 37(10):3418-30, doi: 10.1093/nar/gkp207, PMID: 19336419.
- Brais B, Bouchard JP, Xie YG et al. Short GCG expansions in the PABP2 gene cause oculopharyngeal muscular dystrophy. Nat Genet 1998 18(2):164-7, doi: 10.1038/ng0298-164, PMID: 9462747.
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