Polyadenylate-binding protein 1 is a protein that in humans is encoded by the PABPC1gene.[1] The protein PABP1 binds mRNA and facilitates a variety of functions such as transport 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.[2]
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) shortening and translation initiation. In humans, the PABPs comprise a small nuclear isoform and a conserved gene family that displays at least 3 functional proteins: PABP1 (PABPC1), inducible PABP (iPABP, or PABPC4; MIM 603407), and PABP3 (PABPC3; MIM 604680). In addition, there are at least 4 pseudogenes, PABPCP1 to PABPCP4.[supplied by OMIM][3]
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.[4]
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.[2]
↑Hoshino S, Imai M, Kobayashi T, Uchida N, Katada T (June 1999). "The eukaryotic polypeptide chain releasing factor (eRF3/GSPT) carrying the translation termination signal to the 3'-Poly(A) tail of mRNA. Direct association of erf3/GSPT with polyadenylate-binding protein". The Journal of Biological Chemistry. 274 (24): 16677–80. doi:10.1074/jbc.274.24.16677. PMID10358005.
↑Craig AW, Haghighat A, Yu AT, Sonenberg N (April 1998). "Interaction of polyadenylate-binding protein with the eIF4G homologue PAIP enhances translation". Nature. 392 (6675): 520–3. doi:10.1038/33198. PMID9548260.
Craig AW, Haghighat A, Yu AT, Sonenberg N (April 1998). "Interaction of polyadenylate-binding protein with the eIF4G homologue PAIP enhances translation". Nature. 392 (6675): 520–3. doi:10.1038/33198. PMID9548260.
Afonina E, Stauber R, Pavlakis GN (May 1998). "The human poly(A)-binding protein 1 shuttles between the nucleus and the cytoplasm". The Journal of Biological Chemistry. 273 (21): 13015–21. doi:10.1074/jbc.273.21.13015. PMID9582337.
Hornstein E, Git A, Braunstein I, Avni D, Meyuhas O (January 1999). "The expression of poly(A)-binding protein gene is translationally regulated in a growth-dependent fashion through a 5'-terminal oligopyrimidine tract motif". The Journal of Biological Chemistry. 274 (3): 1708–14. doi:10.1074/jbc.274.3.1708. PMID9880551.
Hoshino S, Imai M, Kobayashi T, Uchida N, Katada T (June 1999). "The eukaryotic polypeptide chain releasing factor (eRF3/GSPT) carrying the translation termination signal to the 3'-Poly(A) tail of mRNA. Direct association of erf3/GSPT with polyadenylate-binding protein". The Journal of Biological Chemistry. 274 (24): 16677–80. doi:10.1074/jbc.274.24.16677. PMID10358005.
Deo RC, Bonanno JB, Sonenberg N, Burley SK (September 1999). "Recognition of polyadenylate RNA by the poly(A)-binding protein". Cell. 98 (6): 835–45. doi:10.1016/S0092-8674(00)81517-2. PMID10499800.
Grosset C, Chen CY, Xu N, Sonenberg N, Jacquemin-Sablon H, Shyu AB (September 2000). "A mechanism for translationally coupled mRNA turnover: interaction between the poly(A) tail and a c-fos RNA coding determinant via a protein complex". Cell. 103 (1): 29–40. doi:10.1016/S0092-8674(00)00102-1. PMID11051545.
Khaleghpour K, Svitkin YV, Craig AW, DeMaria CT, Deo RC, Burley SK, Sonenberg N (January 2001). "Translational repression by a novel partner of human poly(A) binding protein, Paip2". Molecular Cell. 7 (1): 205–16. doi:10.1016/S1097-2765(01)00168-X. PMID11172725.
Bushell M, Wood W, Carpenter G, Pain VM, Morley SJ, Clemens MJ (June 2001). "Disruption of the interaction of mammalian protein synthesis eukaryotic initiation factor 4B with the poly(A)-binding protein by caspase- and viral protease-mediated cleavages". The Journal of Biological Chemistry. 276 (26): 23922–8. doi:10.1074/jbc.M100384200. PMID11274152.
Woods AJ, Roberts MS, Choudhary J, Barry ST, Mazaki Y, Sabe H, Morley SJ, Critchley DR, Norman JC (February 2002). "Paxillin associates with poly(A)-binding protein 1 at the dense endoplasmic reticulum and the leading edge of migrating cells". The Journal of Biological Chemistry. 277 (8): 6428–37. doi:10.1074/jbc.M109446200. PMID11704675.
