Catalogue number
PRO-327
Synonyms
Lupus La protein, Sjoegren syndrome type B antigen, SS-B, La ribonucleoprotein, La autoantigen, SSB, La, LARP3, LA/SS-B, La(SS-B).
Introduction
The La protein is a 47 kDa polypeptide that frequently acts as an autoantigen in systemic lupus erythematosus and Sjogren's syndrome patients. La is involved in various aspects of RNA metabolism, including binding and protecting 3-prime UUU(OH) elements of newly RNA polymerase III - transcribed RNA, processing 5-prime and 3-prime ends of pre-tRNA precursors, acting as an RNA chaperone, and binding viral RNAs linked to hepatitis C virus. It occurs in both the nucleus and the cytoplasm, where it assumes different roles. In the nucleus, La protein facilitates the production of tRNAs, acting as an RNA polymerase III (RNAP III) transcription factor by attaching to the U-rich 3'UTR of nascent transcripts, aiding in their folding and maturation. In the cytoplasm, La protein facilitates the translation of specific mRNAs, acting as a translation factor. As an RNA binding protein (RBP), La protein associates with subsets of mRNAs which contain a 5'-terminal oligopyrimidine (5'TOP) motif known to direct protein synthesis. The binding of La protein to particular classes of RNA molecules regulates their downstream processing, guards them from endonuclease digestion, and organizes their export from the nucleus. La/SS-B appears to be readily disposed to proteolysis, which results in many smaller (42kD, 320, and 270) nevertheless still immunoreactive polypeptides. La/SS-B antigen is strongly conserved across species. Anti-La/SS-B autoantibodies were originally found as precipitating autoantibodies in sera of Sjogren's Syndrome patients and referred to as SjT. Anti-La/SS-B precipitins are most frequently found in Sjogren's Syndrome, Systemic Lupus Erythematosus (SLE) and Subacute Cutaneous Lupus. Also, there seems to be a correlation between anti-La/SS-B and the absence of nephritis in SLE patients.
Description
LA/SS-B Human Recombinant produced in SF9 is a single, glycosylated, polypeptide chain having a calculated molecular mass of 52 kDa, is fused to a hexahistidine purification tag.
The LA/SS-B is purified by proprietary chromatographic techniques.
Source
Sf9 insect cells.
Physical Appearance
Sterile Filtered clear solution.
Formulation
The protein solution contains 20mM HEPES, pH 7.5, 400mM NaCl, 20% Glycerol.
Stability
Store at 4°C if entire vial will be used within 2-4 weeks.
Store, frozen at -20°C for longer periods of time.
Avoid multiple freeze-thaw cycles.
Purity
Greater than 95.0% as determined by SDS-PAGE.
Safety Data Sheet
Usage
Prospec's products are furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals.
