Poly(A)-binding protein

File:RABP.PNG

Poly(A) RNA Binding Protein PABP, PDB 1CVJ

Poly(A)-binding protein is a RNA-binding protein which binds to the poly(A) tail of mRNA. The poly(A) tail is located on the 3' end of mRNA. THe nucleur isoforms selectively binds to around 50 nucleotides and stimulates the activity of Polyadenylate polymerase.

THe cytosolic isoform of eukaryotes Poly(A) binding protein binds to the intiation factor eIF-4G via its C-terminal domain. EIF-4G is bound to eIF-4E, another initiation factor bound to the 5' cap on the 5' end of mRNA. This binding forms the characteristic loop structure of eukaryotic protein synthesis. Poly(A)-binding protein interacting proteins in the cytosol compete for the eIF-4G binding sites.

Genes

• PABPC1, PABPC3, PABPC4, PABPC5

External links

• Poly(A)-Binding+Proteins at the U.S. National Library of Medicine Medical Subject Headings (MeSH)