La domain | |||||||||
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![]() solution structure of the la domain of c-mpl binding protein | |||||||||
Identifiers | |||||||||
Symbol | La | ||||||||
Pfam | PF05383 | ||||||||
InterPro | IPR006630 | ||||||||
SMART | TSPN | ||||||||
PROSITE | PDOC00280 | ||||||||
MEROPS | I75 | ||||||||
SCOP2 | 2mpr / SCOPe / SUPFAM | ||||||||
TCDB | 1.B.3 | ||||||||
CDD | cd07323 | ||||||||
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In molecular biology, the La domain is a conserved protein domain. Human 60 kDa SS-A/Ro ribonucleoproteins (RNPs) are composed of one of the four small Y RNAs and at least two proteins, Ro60 and La. The La protein is a 47 kDa polypeptide that frequently acts as an autoantigen in systemic lupus erythematosus and Sjögren syndrome. [1] In the nucleus, La acts as a RNA polymerase III (RNAP III) transcription factor, while in the cytoplasm, La acts as a translation factor. [2] In the nucleus, La binds to the 3'UTR of nascent RNAP III transcripts to assist in folding and maturation. [3] In the cytoplasm, La recognises specific classes of mRNAs that contain a 5'-terminal oligopyrimidine (5'TOP) motif known to control protein synthesis. [4] The specific recognition is mediated by the N-terminal domain of La, which comprises a La motif and an RNA recognition motif (RRM). The La motif adopts an alpha/beta fold that comprises a winged-helix motif. [5]
Homologous La domain-containing proteins have been identified in a wide range of organisms except Archaea, bacteria and viruses. [6]