Serum amyloid A-1 protein (SAA1) - 500 µg

Frozen Dry Ice

FunctionSerum amyloid A (SAA) proteins function as cytokine-like proteins with roles in the acute phase response, lipid transport and metabolism, cell-cell communication, atherosclerosis, and feedback in inflammatory, neoplastic, immunologic, and protective pathways1. SAA proteins are normally found at low levels in healthy individuals, but after the onset of the acute phase response, SAA levels can increase by 1000-fold within 24 hours, with levels decreasing back to normal when the event resolves. However, elevated levels of SAA can persist when inflammation is chronic. Acute-phase SAA is tightly bound to high-density lipoprotein (HDL) and functions as an apolipoprotein.Mechanism and pathwaysThe human genome encodes four major variants of SAA (SAA1-4), with Saa3 being atranscribed pseudogene1. SAA1 and SAA2 are involved in the classic acute phase response and are synthesized and secreted by the liver (hepatocytes), macrophages, adipocytes, kidney, lung, and mammary gland cells. Transcription of Saa1 and Saa2 is also observed in synovial and brain cells. During the acute phase response, SAA1 expression is regulated by many transcription factors (NF-κB, C/EBP, YY1, AP-2, SAF, Sp1, STAT3), proinflammatory cytokines (IL-1β, IL-6, TNF-α), and glucocorticoids2. SAA4 is constitutively expressed1.SAA1 is a major precursor of amyloid A and is known to form pathogenic amyloid fibrils when over-produced or aberrantly processed2. Additionally, SAA1 is used as a clinical biomarker for inflammatory disorders2 and may be useful as a prognostic marker in the tumor microenvironment3 or for metastasis of hepatocellular4 and renal cell5carcinomas. Additionally, SAA1 has been suggested as a novel therapeutic target of pancreatic cancer6.StructureMature SAA1 protein consists of 104 amino acids and is a hexamer stabilized by its C-terminal tail2. SAA proteins are poorly soluble in aqueous solutions, and concentrations needed to characterize their 3D structure are difficult to acquire1. Heparin sulfate disrupts SAA binding to HDL.