SRP54 Human

SRP54, a 54-kDa protein, functions as a subunit of the signal recognition particle (SRP). This cytoplasmic ribonucleoprotein complex plays a crucial role in protein targeting by directing newly synthesized secretory proteins from the ribosome to the endoplasmic reticulum. Composed of six polypeptides and a 7SL RNA molecule, SRP relies on SRP54, a GTP-binding protein, to directly interact with the signal sequences of nascent secretory and membrane proteins. Autoantibodies targeting SRP, particularly the SRP54 subunit, are found in patients with polymyositis, an autoimmune disorder characterized by chronic muscle inflammation. These autoantibodies can immunoprecipitate several SRP subunits and the RNA component. Anti-SRP autoantibodies are present in approximately 5% of myositis patients, with the prevalence increasing to 18% in Jo-1 autoantibody-negative individuals. The 'anti-SRP syndrome' is a severe, rapidly progressing form of polymyositis marked by acute muscle inflammation, myalgias, and cardiac complications. This syndrome is often associated with a poor response to treatment and a 5-year survival rate of approximately 25%.

This product consists of a full-length cDNA sequence encoding the human SRP54 protein. This protein has a molecular mass of 62kDa (determined at pH 8.9) and is fused to a hexa-histidine tag for purification purposes.

The SRP54 protein is provided in a buffer solution containing 16mM HEPES (pH 8.0), 320mM NaCl, 5mM DTT, 1mM EDTA, 0.16mM GDP, and 20% glycerol.

1. This protein can bind to IgG-type human autoantibodies.

2. This protein can be used as a standard in ELISA tests, including checkerboard analysis with positive and negative serum panels, and in immunodot tests with positive and negative serum panels.

This protein can be used in Western blot analysis with myositis sera or with a monoclonal antibody targeting the hexa-His-tag.

The optimal coating concentration for this protein is 0.5-0.9 µg/ml, which can vary depending on the ELISA plate type and the coating buffer used. This protein is suitable for biotinylation and iodination.

For short-term storage (2-4 weeks), the product can be stored at 4°C. For long-term storage, it should be stored frozen at -20°C. Repeated freeze-thaw cycles should be avoided.

The purity of this protein is greater than 80% as determined by SDS-PAGE analysis.

Signal Recognition Particle 54 kDa protein

Sf9 insect cells.