LA/SS-B Human

The La protein, a 47 kDa polypeptide, is frequently recognized as an autoantigen in individuals with systemic lupus erythematosus and Sjogren's syndrome. This protein plays a crucial role in various RNA metabolic processes, including binding and safeguarding the 3-prime UUU(OH) elements of newly synthesized RNA polymerase III transcripts, processing the 5-prime and 3-prime ends of pre-tRNA precursors, functioning as an RNA chaperone, and interacting with viral RNAs associated with hepatitis C virus. La protein is found in both the nucleus and cytoplasm, where it performs distinct functions. Within the nucleus, it facilitates the production of tRNAs by acting as an RNA polymerase III (RNAP III) transcription factor. It achieves this by attaching itself to the U-rich 3'UTR of nascent transcripts, thereby aiding in their folding and maturation. In the cytoplasm, La protein acts as a translation factor, facilitating the translation of specific mRNAs. As an RNA binding protein (RBP), it associates with subsets of mRNAs containing a 5'-terminal oligopyrimidine (5'TOP) motif, which is known to direct protein synthesis. The binding of La protein to specific classes of RNA molecules regulates their subsequent processing, protects them from endonuclease degradation, and coordinates their export from the nucleus. La/SS-B exhibits a propensity for proteolysis, resulting in the formation of smaller polypeptides (42kD, 320, and 270) that retain their immunoreactivity. Notably, the La/SS-B antigen is highly conserved across different species. Anti-La/SS-B autoantibodies were initially identified as precipitating autoantibodies in the sera of Sjogren's Syndrome patients and were designated as SjT. These anti-La/SS-B precipitins are most commonly observed in Sjogren's Syndrome, Systemic Lupus Erythematosus (SLE), and Subacute Cutaneous Lupus. Interestingly, there appears to be a correlation 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 cells, is a single, glycosylated polypeptide chain with a calculated molecular mass of 52 kDa. It is fused to a hexahistidine purification tag for ease of purification. The LA/SS-B protein undergoes purification using proprietary chromatographic techniques.

A clear solution that has been sterilized by filtration.

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

For short-term storage (2-4 weeks), the protein should be stored at 4°C. For long-term storage, it is recommended to store the protein frozen at -20°C. To maintain protein integrity, avoid repeated freeze-thaw cycles.

The purity of the protein is greater than 95.0% as determined by SDS-PAGE analysis.

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.