Serum Amyloid A editSet type / Edit
«Serum amyloid A (SAA) proteins are a family of apolipoproteins associated with high-density lipoprotein (HDL) in plasma. Different isoforms of SAA are expressed constitutively (constitutive SAA) at different levels or in response to inflammatory stimuli (acute phase SAA). These proteins are produced predominantly by the liver. The conservation of these proteins throughout invertebrates and vertebrates suggests that SAA play a highly essential role in all animals.
Acute-phase serum amyloid A proteins (A-SAA) are secreted during the acute phase of inflammation. These proteins have several roles, including the transport of cholesterol to the liver for secretion into the bile, the recruitment of immune cells to inflammatory sites, and the induction of enzymes that degrade extracellular matrix. A-SAA are implicated in several chronic inflammatory diseases, such as amyloidosis, atherosclerosis, and rheumatoid arthritis. Three acute-phase SAA isoforms have been reported in mice, called SAA1, SAA2, and SAA3. During inflammation, SAA1 and SAA2 are expressed and induced principally in the liver, whereas SAA3 is induced in many distinct tissues. SAA1 and SAA2 genes are regulated in liver cells by the proinflammatory cytokinesIL-1, IL-6, and TNF-α. Both SAA1 and SAA2 are induced up to a 1000-fold in mice under acute inflammatory conditions following exposure to bacterial lipopolysaccharide (LPS). Three A-SAA genes have also been identified in humans, although the third gene, SAA3, is believed to represent a pseudogene that does not generate messenger RNA or protein. Molecular weights of the human proteins are estimated at 11.7 kDa for SAA1 and 12.8 kDa for SAA4.
Modified: 1 month ago on Apr 12, 2019
1 month ago on Apr 12, 2019.