Human factor H-related protein 5 (FHR-5). A new complement-associated protein

J Biol Chem. 2001 Mar 2;276(9):6747-54. doi: 10.1074/jbc.M007495200. Epub 2000 Oct 31.

Abstract

A novel human plasma protein has been identified as a universal component of complement deposits, when complement is detected immunohistochemically in vivo. The protein is homologous to complement factor H and related proteins and has been designated factor H-related protein 5 (FHR-5). FHR-5 was identified by a monoclonal antibody raised using pathologic human glomerular preparations as the immunogen. FHR-5 was purified by affinity chromatography from complement-lysed erythrocytes, and the peptide sequence was obtained. The cDNA was cloned from a human liver library, and FHR-5 was deduced to be a protein containing 551 amino acids organized into nine short consensus repeat motifs. The short consensus repeats of FHR-5 show homology to Factor H and to other Factor H-related proteins, with some unique features demonstrated. Recombinant FHR-5, expressed in insect cells, was shown to bind C3b in vitro. The strong association of FHR-5 with tissue complement deposits in vivo suggests that this additional member of the Factor H family of proteins has a function in complement regulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / immunology
  • Apolipoproteins / analysis
  • Blood Proteins / analysis*
  • Blood Proteins / chemistry
  • Blood Proteins / genetics
  • Blotting, Northern
  • Blotting, Western
  • Cloning, Molecular
  • Complement Factor H* / metabolism
  • Molecular Sequence Data
  • Rabbits
  • Recombinant Proteins / analysis

Substances

  • Antibodies, Monoclonal
  • Apolipoproteins
  • Blood Proteins
  • CFH protein, human
  • CFHR4 protein, human
  • Recombinant Proteins
  • Complement Factor H

Associated data

  • GENBANK/AF295327