PABPC1

PABPC1 is a poly(A) binding protein. The protein shuttles between the nucleus and cytoplasm and binds to the 3' poly(A) tail of eukaryotic messenger RNAs via RNA-recognition motifs. The binding of this protein to poly(A) promotes ribosome recruitment and translation initiation; it is also required for poly(A) shortening which is the first step in mRNA decay. The gene is part of a small gene family including three protein-coding genes and several pseudogenes.

Full Name

Poly(A) Binding Protein Cytoplasmic 1

Function

Binds the poly(A) tail of mRNA, including that of its own transcript, and regulates processes of mRNA metabolism such as pre-mRNA splicing and mRNA stability (PubMed:11051545, PubMed:17212783, PubMed:25480299).

Its function in translational initiation regulation can either be enhanced by PAIP1 or repressed by PAIP2 (PubMed:11051545, PubMed:20573744).

Can probably bind to cytoplasmic RNA sequences other than poly(A) in vivo. Involved in translationally coupled mRNA turnover (PubMed:11051545).

Implicated with other RNA-binding proteins in the cytoplasmic deadenylation/translational and decay interplay of the FOS mRNA mediated by the major coding-region determinant of instability (mCRD) domain (PubMed:11051545).

Involved in regulation of nonsense-mediated decay (NMD) of mRNAs containing premature stop codons; for the recognition of premature termination codons (PTC) and initiation of NMD a competitive interaction between UPF1 and PABPC1 with the ribosome-bound release factors is proposed (PubMed:18447585).

By binding to long poly(A) tails, may protect them from uridylation by ZCCHC6/ZCCHC11 and hence contribute to mRNA stability (PubMed:25480299).
(Microbial infection) Positively regulates the replication of dengue virus (DENV).

Biological Process

Gene silencing by RNA Source: UniProtKB
mRNA polyadenylation Source: UniProtKB
mRNA splicing, via spliceosome Source: UniProtKB
mRNA stabilization Source: UniProtKB
Negative regulation of nuclear-transcribed mRNA catabolic process, nonsense-mediated decay Source: UniProtKB
Nuclear-transcribed mRNA catabolic process, nonsense-mediated decay Source: Reactome
Positive regulation of nuclear-transcribed mRNA catabolic process, deadenylation-dependent decay Source: UniProtKB
Positive regulation of nuclear-transcribed mRNA poly(A) tail shortening Source: UniProtKB
Positive regulation of viral genome replication Source: UniProtKB
Regulation of mRNA stability Source: Reactome
Translational initiation Source: Reactome

Cellular Location

Cytoplasm; Nucleus; Stress granule; Lamellipodium. Localized in cytoplasmic mRNP granules containing untranslated mRNAs (PubMed:17289661). Shuttles between the cytoplasm and the nucleus (PubMed:9582337). During stress and in the absence of DDX3X, localizes to the nucleus (PubMed:21883093). At the leading edge of migrating fibroblasts, colocalizes with DDX3X (PubMed:28733330). Relocalizes to cytoplasmic stress granules upon cellular stress where it colocalizes with ENDOV (PubMed:27573237). In case of HRSV infection, localizes in cytoplasmic inclusion bodies substructures called inclusion bodies associated granules (IBAGs) (PubMed:31649314).

PTM

Phosphorylated by MAPKAPK2.
Methylated by CARM1. Arg-493 is dimethylated, probably to asymmetric dimethylarginine.