Recombinant Human SAA4 protein

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

Serum Amyloid A4 (SAA4) also known as C-SAA is a minor apolipoprotein associated with high-density lipoprotein (HDL) in plasma. SAA4 is a protein of approximately 14 kDa in mass. It is mainly expressed in the liver and secreted into the bloodstream. The protein exists in a tetrameric form and is part of the SAA family which has four known human isoforms: SAA1 SAA2 SAA3 and SAA4.

Biological function summary

SAA4 plays a role in lipid metabolism and transport. Unlike SAA1 and SAA2 SAA4 is not significantly upregulated during acute-phase inflammatory responses. SAA4 works by stabilizing HDL particles and influencing cholesterol transport. It does not participate actively in the inflammatory response which distinguishes it from other SAA proteins. As part of the lipoprotein complex it contributes to maintaining lipid homeostasis.

Pathways

SAA4 participates in pathways associated with lipid transport and metabolism. It is involved in the reverse cholesterol transport pathway an essential system to transfer cholesterol from tissues back to the liver. SAA4 shares functional characteristics with apolipoprotein A1 (ApoA1) another key protein in HDL metabolism. Both proteins contribute to cholesterol efflux and transport although SAA4 has more structural than regulatory roles.

SAA4 has connections to cardiovascular disease and amyloidosis. Researchers have identified altered levels of SAA4 in patients with cardiovascular conditions suggesting a link to atherosclerosis. In amyloidosis although SAA4 is not a primary amyloid component its amyloidogenic potential raises interest in studying its involvement. A clear association exists between SAA4 and ApoA1 in these disorders given their shared role in HDL structure and metabolism.