Evidence for the multimeric structure of ferroportin.

Abstract

Ferroportin (Fpn) (IREG1, SLC40A1, MTP1) is an iron transporter, and mutations in Fpn result in a genetically dominant form of iron overload disease. Previously, we demonstrated that Fpn is a multimer and that mutations in Fpn are dominant negative. Other studies have suggested that Fpn is not a multimer and that overexpression or epitope tags might affect the localization, topology, or multimerization of Fpn. We generated wild-type Fpn with 3 different epitopes, GFP, FLAG, and c-myc, and expressed these constructs in cultured cells. Co-expression of any 2 different epitope-tagged proteins in the same cell resulted in their quantitative coimmunoprecipitation. Treatment of Fpn-GFP/Fpn-FLAG-expressing cells with crosslinking reagents resulted in the crosslinking of Fpn-GFP and Fpn-FLAG. Western analysis of rat glioma C6 cells or mouse bone marrow macrophages exposed to crosslinking reagents showed that endogenous Fpn is a dimer. These results support the hypothesis that the dominant inheritance of Fpn-iron overload disease is due to the dominant-negative effects of mutant Fpn proteins.

• Authors: Ivana De Domenico, Diane McVey Ward, Giovanni Musci, Jerry Kaplan
• Journal: Blood (Blood) Vol. 109 Issue 5 Pg. 2205-9 (Mar 01 2007) ISSN: 0006-4971 [Print] United States
• PMID: 17077321 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Cation Transport Proteins
• Epitopes
• metal transporting protein 1

Topics

• Animals
• Cation Transport Proteins (genetics, immunology, metabolism)
• Cell Line
• Epitopes (immunology)
• Humans
• Mice
• Protein Binding
• Rats