Serum amyloid A1 (SAA1) is a protein that in humans is encoded by the SAA1 gene. SAA1 is a major acute-phase protein mainly produced by hepatocytes in response to infection, tissue injury and malignancy. When released into blood circulation, SAA1 is present as an apolipoprotein associated with high-density lipoprotein (HDL). The gene coding for human SAA1 is one of the 4 SAA genes mapped to a region in the short arm on Chromosome 11. The product of human SAA1 is a pre-protein of 122 amino acids, with a cleavable signal peptide of 18 amino acids. Mature SAA1 consists of 104 amino acids with an apparent molecular weight of 12,500. Systemic AA amyloidosis is a world-wide occurring protein misfolding disease of humans and animals. It arises from the formation of amyloid fibrils from serum amyloid A (SAA) protein. Mice express several SAA family members, similar to humans, but only SAA1.1 is a major fibril precursor protein, corresponding to the prime role of SAA1.1 in Caucasian populations. SAA1.1 is an acute phase protein that becomes strongly upregulated during inflammation. Chronic inflammatory conditions, such as tuberculosis, leprosy and rheumatoid arthritis, are risk factors for the development of systemic AA amyloidosis. Here you can see a recent cryoEM structure of the amyloid fibrils formed by SAA1.1 protein in mice (PDB code: 6ZCG)

#molecularart ... #amyloid ... #mice ... #beta ... #cryoem ... #SAA1

Structure rendered with @proteinimaging and depicted with @corelphotopaint