Sjogren Syndrome/Scleroderma Autoantigen 1 (SSSCA1)

The centromere plays an essential role in the pairing and partitioning of replicated chromosomes in mitosis and meiosis and is recognized by anticentromere antibodies in patients with autoimmune disorders.

The deduced 199-amino acid, leucine-rich protein has an N terminus with many charged residues and a potential phosphorylation site; 2 short proline-rich stretches; and a potential C-terminal phosphorylation site. Immunofluorescence analysis failed to demonstrate centromeric or other staining. Immunoblot analysis with recombinant SSSCA1 determined that approximately 2% of patients with anticentromere antibodies had anti-SSSCA1 antibodies, while less than 1% of autoimmune patients without anticentromere antibodies had anti-SSSCA1 antibodies.