Cleavage And Polyadenylation Factor I (CLP1)

The deduced 425-amino acid protein is valine- and leucine-rich and contains a domain sharing similarity with the ATP/GTP-binding domain of ABC transporters. It also has a possible tyrosine kinase phosphorylation site. Northern blot analysis detected a major 2.0-kb transcript that was expressed ubiquitously, with highest expression in testis and skeletal muscle.

CLP1 interacted with CFIm and cleavage-polyadenylation specificity factor (CPSF), suggesting that it bridges these two 3-prime end processing factors within the cleavage complex.the physiologic role of CLP1 as the RNA kinase that phosphorylates the 5-prime end of the 3-prime exon during human tRNA splicing, allowing the subsequent ligation of both exon halves by an unknown tRNA ligase.