Association of the macrophage activating factor (MAF) precursor activity with polymorphism in vitamin D-binding protein.

Abstract

BACKGROUND:

Serum vitamin D-binding protein (Gc protein or DBP) is a highly expressed polymorphic protein, which is a precursor of the inflammation-primed macrophage activating factor, GcMAF, by a cascade of carbohydrate processing reactions. In order to elucidate the relationship between Gc polymorphism and GcMAF precursor activity, we estimated the phagocytic ability of three homotypes of Gc protein, Gc1F-1F, Gc1S-1S and Gc2-2, through processing of their carbohydrate moiety.

MATERIALS AND METHODS:

We performed Gc typing of human serum samples by isoelectric focusing (IEF). Gc protein from human serum was purified by affinity chromatography with 25-hydroxyvitamin D3-sepharose. A phagocytosis assay of Gc proteins, modified using beta-glycosidase and sialidase, was carried out.

RESULTS:

The Gc1F-1F phenotype was revealed to possess Galbeta1-4GalNAc linkage by the analysis of GcMAF precursor activity using beta1-4 linkage-specific galactosidase from jack bean. The GcMAF precursor activity of the Gc1F-1F phenotype was highest among three Gc homotypes.

CONCLUSION:

The Gc polymorphism and carbohydrate diversity of Gc protein are significant for its pleiotropic effects.

• Authors: Hideko Nagasawa, Hideyuki Sasaki, Yoshihiro Uto, Shinichi Kubo, Hitoshi Hori
• Journal: Anticancer research (Anticancer Res) 2004 Sep-Oct Vol. 24 Issue 5C Pg. 3361-6 ISSN: 0250-7005 [Print] Greece
• PMID: 15515432 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Carbohydrates
• Lymphokines
• Protein Precursors
• Vitamin D-Binding Protein
• macrophage aggregation factor
• beta-Galactosidase

Topics

• Adult
• Animals
• Carbohydrate Metabolism
• Carbohydrates (chemistry)
• Chromatography, Affinity
• Female
• Humans
• Isoelectric Focusing
• Lymphokines (metabolism)
• Mice
• Middle Aged
• Models, Molecular
• Phagocytosis
• Phenotype
• Polymorphism, Genetic
• Protein Conformation
• Protein Precursors (metabolism)
• Vitamin D-Binding Protein (blood, classification, genetics, isolation & purification)
• beta-Galactosidase (metabolism)