InterPro: IPR002344 Lupus La protein

The La protein is a 47 kDa polypeptide that often acts as an autoantigen in systemic lupus erythematosus and Sjogren's syndrome patients [1]. It occurs in both the nucleus and the cytoplasm, where it takes on different roles [2]. In the nucleus, La facilitates the production of tRNAs, acting as a RNA polymerase III (RNAP III) transcription factor by binding to the U-rich 3'UTR of nascent transcripts, assisting in their folding and maturation [3]. In the cytoplasm, La facilitates the translation of specific mRNAs, acting as a translation factor. As a RNA binding protein (RBP), La associates with subsets of mRNAs that contain a 5'-terminal oligopyrimidine (5'TOP) motif known to control protein synthesis. The binding of La to specific classes of RNA molecules regulates their downstream processing, protects them from endonuclease digestion, and organises their export from the nucleus [4, 5, 6, 7].