scholarly journals Phosphorylation of human serum amyloid A protein by protein kinase C

1988 ◽  
Vol 255 (1) ◽  
pp. 29-34 ◽  
Author(s):  
A E Nel ◽  
M C De Beer ◽  
E G Shephard ◽  
A F Strachan ◽  
M L Vandenplas ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Acute Phase ◽  
Serum Amyloid A ◽  
Density Lipoprotein ◽  
Acute Phase Reactant ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Kinase C ◽  
Serum Amyloid A Protein

Monokine-induced hepatic secretion of serum amyloid A protein (apo-SAA), an acute-phase reactant, is followed by rapid association with high-density lipoprotein (HDL) in plasma. Plasma clearance of apo-SAA is more rapid than any of the other HDL apolipoproteins. It has been shown that, of the acute-phase HDL3 apolipoproteins, apo-SAA preferentially associates with neutrophil membranes. HDL apolipoproteins have been shown to activate protein kinase C in endothelial cells. We therefore investigated potential phosphorylation of HDL3 apolipoproteins by protein kinase C. Apo-SAA was the only apolipoprotein phosphorylated (Km = 12 mM). Phosphorylation of the apo-SAA-containing HDL3 particle was selective for the more basic isoforms of apo-SAA (pI 7.0, 7.4, 7.5 and 8.0), with more acidic isoforms being phosphorylated when delipidated acute-phase apolipoproteins were used as substrate. However, phosphorylation was not in itself responsible for the establishment of the apo-SAA isoforms.

scholarly journals Acute-phase high-density lipoprotein in the rat does not contain serum amyloid A protein

1987 ◽  
Vol 242 (1) ◽  
pp. 301-303 ◽  
Author(s):  
M L Baltz ◽  
I F Rowe ◽  
D Caspi ◽  
W G Turnell ◽  
M B Pepys
Keyword(s):  
High Density Lipoprotein ◽  
Acute Phase ◽  
Serum Amyloid A ◽  
Amyloid Fibrils ◽  
Density Lipoprotein ◽  
Lipid Binding ◽  
High Density ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Serum Amyloid A Protein

Serum amyloid A protein (SAA) is an acute-phase apolipoprotein of high-density lipoprotein (HDL). Its N-terminal sequence is identical with that of amyloid A protein (AA), the subunit of AA amyloid fibrils. However, rats do not develop AA amyloidosis, and we report here that neither normal nor acute-phase rat HDL contains a protein corresponding to SAA of other species. mRNA coding for a sequence homologous with the C-terminal but not with the N-terminal part of human SAA is synthesized in greatly increased amounts in acute-phase rat liver. These observations indicate that the failure of rats to develop AA amyloid results from the absence of most of the AA-like part of their SAA-like protein, and that the N-terminal portion of SAA probably contains the lipid-binding sequences.

The acute phase response and C-reactive protein

2020 ◽  
pp. 2199-2207
Author(s):  
Mark B. Pepys
Keyword(s):  
Acute Phase ◽  
Acute Phase Response ◽  
Serum Amyloid A ◽  
Acute Phase Proteins ◽  
Phase Response ◽  
Serum Amyloid ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Amyloid A ◽  
Serum Amyloid A Protein

The acute phase response—trauma, tissue necrosis, infection, inflammation, and malignant neoplasia induce a complex series of nonspecific systemic, physiological, and metabolic responses including fever, leucocytosis, catabolism of muscle proteins, greatly increased de novo synthesis and secretion of a number of ‘acute phase’ plasma proteins, and decreased synthesis of albumin, transthyretin, and high- and low-density lipoproteins. The altered plasma protein concentration profile is called the acute phase response. Acute phase proteins—these are mostly synthesized by hepatocytes, in which transcription is controlled by cytokines including interleukin 1, interleukin 6, and tumour necrosis factor. The circulating concentrations of complement proteins and clotting factors increase by up to 50 to 100%; some of the proteinase inhibitors and α‎1-acid glycoprotein can increase three- to fivefold; but C-reactive protein (CRP) and serum amyloid A protein (an apolipoprotein of high-density lipoprotein particles) are unique in that their concentrations can change by more than 1000-fold. C-reactive protein—this consists of five identical, nonglycosylated, noncovalently associated polypeptide subunits. It binds to autologous and extrinsic materials which contain phosphocholine, including bacteria and their products. Ligand-bound CRP activates the classical complement pathway and triggers the inflammatory and opsonizing activities of the complement system, thereby contributing to innate host resistance to pneumococci and probably to recognition and safe ‘scavenging’ of cellular debris. Clinical features—(1) determination of CRP in serum or plasma is the most useful marker of the acute phase response in most inflammatory and tissue damaging conditions. (2) Acute phase proteins may be harmful in some circumstances. Sustained increased production of serum amyloid A protein can lead to the deposition of AA-type, reactive systemic amyloid.

scholarly journals Human serum amyloid A protein. Behaviour in aqueous and urea-containing solutions and antibody production

1989 ◽  
Vol 263 (2) ◽  
pp. 365-370 ◽  
Author(s):  
A F Strachan ◽  
E G Shephard ◽  
D U Bellstedt ◽  
G A Coetzee ◽  
D R van der Westhuyzen ◽  
...  
Keyword(s):  
Human Serum ◽  
Serum Amyloid A ◽  
Gel Filtration ◽  
Density Lipoprotein ◽  
High Titre ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Buffer Solutions ◽  
Wide Range ◽  
Serum Amyloid A Protein

Human serum amyloid A protein (apo-SAA) can be prepared by gel filtration of delipidated acute-phase high-density lipoprotein in the presence of urea. The resultant apo-SAA is soluble (greater than 90% solubility) in a wide range of buffer solutions, with all of the six major isoforms of apo-SAA being equally soluble. In urea-containing solutions the isoforms behave qualitatively differently in various urea concentrations, probably reflecting subtle primary-structure variations. The higher-pI isoforms are only completely unfolded at greater than 7 M-urea. By immunizing with apo-SAA adsorbed to acid-treated bacteria (Salmonella minnesota R595), high-titre antibodies can easily be elicited in rabbits.

Serum amyloid A: A typical acute-phase reactant in rainbow trout?

2008 ◽  
Vol 32 (10) ◽  
pp. 1160-1169 ◽  
Author(s):  
Franz Villarroel ◽  
Alin Casado ◽  
Jorge Vásquez ◽  
Ella Matamala ◽  
Bruno Araneda ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Acute Phase ◽  
Serum Amyloid A ◽  
Acute Phase Reactant ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Phase Reactant

scholarly journals Heparan Sulfate Dissociates Serum Amyloid A (SAA) from Acute-phase High-density Lipoprotein, Promoting SAA Aggregation

2012 ◽  
Vol 287 (30) ◽  
pp. 25669-25677 ◽  
Author(s):  
Fredrik Noborn ◽  
John B. Ancsin ◽  
Wimal Ubhayasekera ◽  
Robert Kisilevsky ◽  
Jin-Ping Li
Keyword(s):  
High Density Lipoprotein ◽  
Heparan Sulfate ◽  
Acute Phase ◽  
Serum Amyloid A ◽  
Density Lipoprotein ◽  
High Density ◽  
Serum Amyloid ◽  
Amyloid A

Abstract 388: Impact of Individual Acute Phase Serum Amyloid A Isoforms on HDL Metabolism in Mice

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Maria C De Beer ◽  
Myung-Hee Kim ◽  
Joanne M Wroblewski ◽  
Richard C Charnigo ◽  
Ailing Ji ◽  
...  
Keyword(s):  
Acute Phase ◽  
Plasma Clearance ◽  
Serum Amyloid A ◽  
Biological Activities ◽  
Acute Phase Reactant ◽  
Serum Amyloid ◽  
Minor Role ◽  
Clearance Rates ◽  
Amyloid A ◽  
Significant Difference

The acute phase reactant serum amyloid A (SAA) is an HDL apolipoprotein that exhibits biological activities as a pro-inflammatory mediator, but its physiological function(s) are poorly understood. Possible functional differences between SAA1.1 and SAA2.1, the two major SAA isoforms, are also unclear. Mice deficient in either SAA1.1 or SAA2.1 were used to investigate SAA isoform plasma clearance rates and effects on HDL structure, composition and apolipoprotein catabolism. The absence of either isoform did not affect the size of the normally enlarged HDL found in acute phase wild type mice, and did not result in significant changes in HDL lipid composition. Plasma clearance rates of normal and acute phase HDL apolipoproteins were determined using native HDL particles. The fractional clearance rates (FCR’s) of apoA-I, apoA-II and SAA were distinct, indicating that neither normal nor acute phase particles are cleared as intact particles. No significant difference was found between the FCR’s of SAA1.1 and SAA2.1 in acute phase mice, suggesting that the selective deposition of SAA1.1 observed in amyloid plaques is not associated with a difference in the rates of plasma clearance of the isoforms. In the absence of the HDL receptor SR-BI, the clearance rate of SAA was reduced by about 30% and remained significantly greater compared to that of apoA-I and apoA-II, indicating a relatively minor role of SR-BI in SAA clearance. These studies contribute to our understanding of the metabolism of SAA and its effects on acute phase HDL composition and catabolism.

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