TI  - Crystal structure of the hereditary haemochromatosis protein  <prot>HFE</prot>  complexed
      with  <prot><prot>transferrin</prot>  receptor</prot> .
PG  - 46-53
AB  - <prot>HFE</prot> is related to major histocompatibility complex (MHC) class I proteins
      and is mutated in the iron-overload disease hereditary haemochromatosis.
       <prot>HFE</prot>  binds to the  <prot><prot>transferrin</prot> receptor</prot> (<prot>TfR</prot>) , a receptor by which cells
      acquire iron-loaded <prot>transferrin</prot>. The 2.8 A crystal structure of a complex
      between the extracellular portions of  <prot>HFE</prot>  and  <prot>TfR</prot>  shows two <prot>HFE</prot> molecules
      which grasp each side of a twofold symmetric <prot>TfR</prot> dimer. On a cell membrane
      containing both proteins, <prot>HFE</prot> would 'lie down' parallel to the membrane,
      such that the <prot>HFE</prot> helices that delineate the counterpart of the MHC
      peptide-binding groove make extensive contacts with helices in the <prot>TfR</prot>
      dimerization domain. The structures of <prot>TfR</prot> alone and complexed with <prot>HFE</prot>
      differ in their domain arrangement and dimer interfaces, providing a
      mechanism for communicating binding events between <prot>TfR</prot> chains. The  <prot>HFE</prot> - <prot>TfR</prot> 
      complex suggests a binding site for transferrin on <prot>TfR</prot> and sheds light
      upon the function of <prot>HFE</prot> in regulating iron homeostasis.
AD  - Division of Biology, California Institute of Technology, Pasadena 91125,
