| La domain | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 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 | ||||||||
| |||||||||
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]