Sjögren syndrome type B antigen (SSB)

Sjögren syndrome type B antigen (SSB), also known as the Lupus La protein, is a ubiquitous and essential RNA-binding protein encoded by the SSB gene[1][2][5]. SSB/La recognizes and binds the 3′ poly(U) termini of nascent RNA polymerase III transcripts, protecting these RNAs from exonucleolytic degradation and facilitating proper folding, especially in pre-tRNAs and 5S rRNA precursors[1][2][5]. It also functions as an RNA chaperone, is involved in the maturation of small regulatory RNAs (including pre-microRNAs), and participates in the biogenesis and regulation of viral RNAs during infections such as hepatitis C, Coxsackievirus, and others[2][4]. SSB/La interacts with several cellular pathways, modulating processes including cell survival, RNA interference, and the antiviral interferon response via RIG-I interaction[4]. Notably, SSB is a major autoantigen in autoimmune diseases such as Sjögren’s syndrome and systemic lupus erythematosus, where patients frequently develop anti-SSB autoantibodies[1][2][4][5]. These autoantibodies serve as important diagnostic markers and may contribute to disease pathogenesis by targeting RNA-protein complexes. SSB is also implicated in X chromosome inactivation, where it stabilizes and helps fold the Xist RNA required for this process[3]. No drugs directly and specifically target SSB/La protein; therapy addresses underlying autoimmune mechanisms or disease effects rather than SSB modulation itself[1][2][5]. References: Information is synthesized and directly supported by current sources[1][2][3][4][5].

Other names

Lupus La proteinLa autoantigenLa ribonucleoproteinSjoegren syndrome type B antigenSS-BLa proteinLARP3La/SSBLa ribonucleoprotein domain family, member 3Sjogren syndrome antigen BLupus La antigenSS-B/La proteinautoantigen La

Not directly targeted pharmacologically; in autoimmunity, autoantibodies against SSB are diagnostic and pathogenic[1][2][5].