Polyadenylate-binding protein 4 (PABPC4)

Polyadenylate-binding protein 4 (PABPC4), encoded by the PABPC4 gene, is a member of the poly(A)-binding protein (PABP) family that binds to the poly(A) tail of eukaryotic mRNAs[3][5]. PABPC4 is primarily localized in the cytoplasm, where it regulates the stability and translation of specific mRNA subsets, particularly those with labile or shortened poly(A) tails. It is distinct from the major isoform (PABPC1) and fulfills nonredundant roles in posttranscriptional gene regulation and erythroid differentiation[1]. In activated T cells, PABPC4 expression is upregulated and may be necessary for stabilizing labile mRNAs during immune responses[3][5]. It is also known as APP-1 (activated-platelet protein 1), participating in platelet and megakaryocyte function. Recent research identifies a role for PABPC4 in antiviral defense, where it suppresses coronavirus replication through selective autophagy-mediated degradation of viral nucleocapsid proteins[2][5]. The protein is dynamically regulated in response to cellular stress and can relocalize to the nucleus, influencing global translation rates. There are currently no clinically approved drugs known to target PABPC4, nor is it established as a therapeutic target, biomarker, or source of major safety concerns.

Other names

Poly(A)-binding protein 4PABP4iPABPAPP-1Inducible poly(A)-binding proteinActivated-platelet protein 1Poly(A) binding protein cytoplasmic 4 (inducible form)