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 wildtype 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 mousebone marrow macrophages exposed to crosslinking reagentsshowedthat 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.

Evidence for the multimeric structure of ferroportin

MUSCI, Giovanni;
2007

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 wildtype 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 mousebone marrow macrophages exposed to crosslinking reagentsshowedthat 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.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11695/6824
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 53
  • ???jsp.display-item.citation.isi??? 52
social impact