PABPC1

Polyadenylate-binding protein 1 is a protein that in humans is encoded by the PABPC1 gene.^[5] The protein PABP1 binds mRNA and facilitates a variety of functions such as transport into and out of the nucleus, degradation, translation, and stability. There are two separate PABP1 proteins, one which is located in the nucleus (PABPN1) and the other which is found in the cytoplasm (PABPC1). The location of PABP1 affects the role of that protein and its function with RNA.^[6]

PABPC1
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1CVJ, 1G9L, 1JGN, 1JH4, 2K8G, 2RQG, 2RQH, 2X04, 3KTP, 3KTR, 3KUI, 3KUJ, 3KUR, 3KUS, 3KUT, 3PKN, 3PTH, 4F02, 4F25, 4F26, 5DX1, 5DXA, 5DX8, 2D9P
Identifiers
Aliases	PABPC1, PAB1, PABP, PABP1, PABPC2, PABPL1, poly(A) binding protein cytoplasmic 1
External IDs	OMIM: 604679; MGI: 1349722; HomoloGene: 37638; GeneCards: PABPC1; OMA:PABPC1 - orthologs
Gene location (Human) Chr. Chromosome 8 (human)[1] Band 8q22.3 Start 100,685,816 bp[1] End 100,722,809 bp[1]
Gene location (Mouse) Chr. Chromosome 15 (mouse)[2] Band 15|15 B3.1 Start 36,595,905 bp[2] End 36,609,912 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in parotid gland pylorus gonad amniotic fluid vulva tonsil nipple trabecular bone monocyte oral cavity Top expressed in tail of embryo genital tubercle ventricular zone yolk sac spermatocyte morula neural layer of retina spermatid embryo lip More reference expression data BioGPS n/a
Gene ontology Molecular function protein binding nucleic acid binding protein C-terminus binding translation activator activity poly(U) RNA binding poly(A) binding mRNA 3'-UTR binding RNA binding mRNA binding Cellular component focal adhesion catalytic step 2 spliceosome cytoplasmic stress granule cytoplasm cytoplasmic ribonucleoprotein granule spliceosomal complex membrane extracellular exosome nucleus cytosol dendrite ribonucleoprotein granule synapse messenger ribonucleoprotein complex ribonucleoprotein complex Biological process nuclear-transcribed mRNA catabolic process, nonsense-mediated decay mRNA stabilization mRNA splicing, via spliceosome regulation of mRNA stability RNA splicing mRNA polyadenylation mRNA processing nuclear-transcribed mRNA poly(A) tail shortening positive regulation of viral genome replication translational initiation negative regulation of nuclear-transcribed mRNA catabolic process, nonsense-mediated decay positive regulation of translation gene silencing positive regulation of nuclear-transcribed mRNA poly(A) tail shortening positive regulation of nuclear-transcribed mRNA catabolic process, deadenylation-dependent decay Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 26986 18458 Ensembl ENSG00000070756 ENSMUSG00000022283 UniProt P11940 P29341 RefSeq (mRNA) NM_002568 NM_008774 RefSeq (protein) NP_002559 NP_032800 Location (UCSC) Chr 8: 100.69 – 100.72 Mb Chr 15: 36.6 – 36.61 Mb PubMed search [3] [4]
Wikidata
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Function

The poly(A)-binding protein (PAB or PABP), which is found complexed to the 3' poly(A) tail of eukaryotic mRNA, is required for poly(A) lengthening and the termination of translation. In humans, the PABPs comprise a small nuclear isoform and a conserved gene family of other poly(A)-binding proteins.[supplied by OMIM]^[7]

PABPC1 is usually diffused within the cytoplasm and concentrated at sites of high mRNA concentration such as stress granules, processing bodies, and locations of high translational activity. PABPC1 is also associated with nonsense-mediated mRNA decay (NMD). PABPC1 binds to the poly(A) tail and interact with eIF4G, which stabilizes the circularization of mRNAs. This structure is required for the prevention of mRNA degradation via NMD.^[8]

In the nucleus PABP1 binds to the poly(A) tails of pre-mRNAs to facilitate stability, export, transport, and degradation. PABP1 binding is also required for nuclear-mediated degradation. PABPC1 contains four RNA-recognition motifs (RRMs). The first two, RRM1 and RRM2, bind both α-importin and the poly(A) tail of processed mRNA. This feature prevents mRNA from going back into the nucleus.^[6]

Interactions

PABPC1 has been shown to interact with:

• ANAPC5,^[9]
• CNOT7,^[10]
• EIF4G3,^[11]
• EIF4G1,^[11]
• GSPT2,^[12]
• PAIP1,^[13][14] and
• PAIP2.^[15]