Serum Amyloid P Component (SAP) Interactome in Human Plasma Containing Physiological Calcium Levels

Ebbe Toftgaard Poulsen; Kata Wolff Pedersen; Anna Maria Marzeda; Jan J Enghild

doi:10.1021/acs.biochem.6b01027

Serum Amyloid P Component (SAP) Interactome in Human Plasma Containing Physiological Calcium Levels

Biochemistry. 2017 Feb 14;56(6):896-902. doi: 10.1021/acs.biochem.6b01027. Epub 2017 Feb 1.

Authors

Ebbe Toftgaard Poulsen¹, Kata Wolff Pedersen¹, Anna Maria Marzeda¹, Jan J Enghild¹

Affiliation

¹ Department of Molecular Biology and Genetics and Interdisciplinary Nanoscience Center, Aarhus University , Gustav Wieds Vej 10, Aarhus, Denmark.

PMID: 28098450
DOI: 10.1021/acs.biochem.6b01027

Abstract

The pentraxin serum amyloid P component (SAP) is secreted by the liver and found in plasma at a concentration of approximately 30 mg/L. SAP is a 25 kDa homopentamer known to bind both protein and nonprotein ligands, all in a calcium-dependent manner. The function of SAP is unclear but likely involves the humoral innate immune system spanning the complement system, inflammation, and coagulation. Also, SAP is known to bind to the generic structure of amyloid deposits and possibly to protect them against proteolysis. In this study, we have characterized the SAP interactome in human plasma containing the physiological Ca²⁺ concentration using SAP affinity pull-down and co-immunoprecipitation experiments followed by mass spectrometry analyses. The analyses resulted in the identification of 33 proteins, of which 24 were direct or indirect interaction partners not previously reported. The SAP interactome can be divided into categories that include apolipoproteins, the complement system, coagulation, and proteolytic regulation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Antibodies, Immobilized / metabolism
Antibodies, Monoclonal / metabolism
Antithrombins / pharmacology
Apolipoproteins / blood
Apolipoproteins / chemistry
Apolipoproteins / isolation & purification
Apolipoproteins / metabolism
Blood Coagulation Factors / analysis
Blood Coagulation Factors / chemistry
Blood Coagulation Factors / isolation & purification
Blood Coagulation Factors / metabolism
Blood Proteins / analysis
Blood Proteins / chemistry
Blood Proteins / isolation & purification
Blood Proteins / metabolism*
Calcium / blood*
Chromatography, High Pressure Liquid
Complement System Proteins / analysis
Complement System Proteins / chemistry
Complement System Proteins / isolation & purification
Complement System Proteins / metabolism
Female
Hirudins / pharmacology
Humans
Immunity, Innate*
Immunoprecipitation
Ligands
Male
Peptide Fragments / analysis
Peptide Fragments / chemistry
Peptide Fragments / isolation & purification
Peptide Fragments / metabolism
Peptide Fragments / pharmacology
Proteolysis
Recombinant Proteins / pharmacology
Serum Amyloid P-Component / analysis
Serum Amyloid P-Component / antagonists & inhibitors
Serum Amyloid P-Component / isolation & purification
Serum Amyloid P-Component / metabolism*
Spectrometry, Mass, Electrospray Ionization
Tandem Mass Spectrometry

Substances

Antibodies, Immobilized
Antibodies, Monoclonal
Antithrombins
Apolipoproteins
Blood Coagulation Factors
Blood Proteins
Hirudins
Ligands
Peptide Fragments
Recombinant Proteins
Serum Amyloid P-Component
Complement System Proteins
Calcium
bivalirudin