Figure 1.

PABPC1 is a common target for viral perturbation of cellular processes. RNA viruses have developed a variety of strategies to interfere with or usurp the cytoplasmic poly(A)-binding protein PABPC1. This interference generally shuts down the translation of host-cell mRNAs as well as potentially exposing them to rapid degradation by the RNA decay machinery. (a) A variety of picornaviruses [22], caliciviruses [23] and HIV [24] encode proteases (for example, poliovirus 2A) that specifically cleave PABPC1. (b) The rotavirus nsp3 protein [25], as well as the KSHV SOX protein [2], relocalizes PABPC1 to the nucleus. Interestingly, unlike SOX, nsp3-induced relocalization does not appear to result in increased mRNA decay. (c) Rubella virus capsid protein specifically binds to PABPC1, sequestering the protein and presumably preventing its binding to cellular mRNAs [26]. (d) Despite the absence of a poly(A) tract, sequences in the 3' untranslated region of dengue virus can specifically bind PABPC1 [27] and recruit it for use by viral mRNAs. ORF, open reading frame.