LA/SS-B Human, Biotin

The La protein, a 47 kDa polypeptide, frequently acts as an autoantigen in individuals with systemic lupus erythematosus and Sjogren's syndrome. This protein plays a crucial role in RNA metabolism, including binding and protecting the 3' UUU(OH) ends of newly transcribed RNA polymerase III transcripts. Moreover, it is involved in processing the 5' and 3' ends of pre-tRNA precursors, acting as an RNA chaperone, and binding viral RNAs associated with the hepatitis C virus. La protein is present in both the nucleus and cytoplasm, where it performs distinct functions. In the nucleus, it facilitates the production of tRNAs by acting as an RNA polymerase III (RNAP III) transcription factor. This is achieved through its attachment to the U-rich 3'UTR of nascent transcripts, aiding in their folding and maturation. Conversely, in the cytoplasm, La protein functions as a translation factor, facilitating the translation of specific mRNAs. It accomplishes this by associating with subsets of mRNAs containing a 5'-terminal oligopyrimidine (5'TOP) motif, known to direct protein synthesis. As an RNA binding protein (RBP), La protein's association with specific RNA molecules regulates their downstream processing, protects them from endonuclease digestion, and organizes their export from the nucleus. La/SS-B exhibits susceptibility to proteolysis, resulting in smaller polypeptides (42kD, 320, and 270) that retain immunoreactivity. Notably, the La/SS-B antigen demonstrates strong conservation across different species. Anti-La/SS-B autoantibodies were initially identified as precipitating autoantibodies in the sera of Sjogren's Syndrome patients and designated as SjT. These precipitins are most commonly observed in Sjogren's Syndrome, Systemic Lupus Erythematosus (SLE), and Subacute Cutaneous Lupus. Interestingly, a correlation appears to exist between the presence of anti-La/SS-B antibodies and the absence of nephritis in SLE patients.

LA/SS-B Human Recombinant, produced in SF9 insect cells, is a single, glycosylated polypeptide chain with a calculated molecular mass of 48 kDa. This recombinant protein is expressed with a -6x His tag at the N-terminus and purified using proprietary chromatographic techniques.

Sterile Filtered, clear solution.

The protein solution is formulated in 20mM HEPES buffer at pH 7.5, containing 400mM NaCl and 20% Glycerol.

For short-term storage (2-4 weeks), keep at 4°C. For extended periods, store frozen at -20°C. Minimize repeated freeze-thaw cycles.

Purity exceeds 80.0% as determined by SDS-PAGE analysis.

1. Binds to IgG type human autoantibodies. 2. Suitable for use in functional Streptavidin-based ELISA tests to analyze positive and negative samples.

Lupus La protein, Sjoegren syndrome type B antigen, SS-B, La ribonucleoprotein, La autoantigen, SSB, La, LARP3, LA/SS-B, La(SS-B).

Sf9 insect cells.