Serum amyloid A
Chr. 11 p15.1 | |||||||
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Human Serum amyloid A2 | |||||||
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Identifiers | |||||||
Symbol | Chr. 11 p15.1-p14 | ||||||
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Human Serum amyloid A3, pseudogene | |||||||
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Identifiers | |||||||
Symbol | SAA3P | ||||||
Alt. symbols | SAA3 | ||||||
Chr. 11 p15.1-p14 | |||||||
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Human Serum amyloid A4 | |||||||
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Identifiers | |||||||
Symbol | SAA4 | ||||||
Alt. symbols | C-SAA | ||||||
Chr. 11 p15.1-p14 | |||||||
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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 SAAs) at different levels or in response to inflammatory stimuli (acute phase SAAs). These proteins are produced predominantly by the liver.[1]
Acute-phase serum amyloid A proteins
Acute-phase serum amyloid A proteins (A-SAAs) are secreted during the acute phase of
Serum amyloid A (SAA) is also an acute phase marker that responds rapidly. Similar to CRP, levels of acute-phase SAA increase within hours after inflammatory stimulus, and the magnitude of increase may be greater than that of CRP. Relatively trivial inflammatory stimuli can lead to SAA responses. It has been suggested that SAA levels correlate better with disease activity in early inflammatory joint disease than do ESR and CRP. Although largely produced by hepatocytes, more recent studies show that SAA is produced by adipocytes as well, and its serum concentration is associated with body mass index.[7]
Constitutive serum amyloid A proteins
A fourth SAA (SAA4) was identified in humans and is expressed constitutively in the liver and, thus, is defined as a constitutive SAA (C-SAA).[8] A similar protein that is now also called SAA4 has since been identified in the mouse; it had originally been designated SAA5.[9][10]
References
- PMID 10504381.
- ^ PMID 15944321.
- S2CID 26076389.
- PMID 1755958.
- ^ "SAA1 - Serum amyloid A-1 protein precursor - Homo sapiens (Human) - SAA1 gene & protein".
- ^ https://www.uniprot.org/blast/?about=P35542[19-130]&key=Chain&id=PRO_0000031583[bare URL]
- ISBN 978-1-4160-0287-1.
- PMID 7686132.
- PMID 8308037.
- PMID 8661036.