TI  - The   <prot>glut 1</prot>   glucose transporter interacts with  <prot>calnexin</prot>  and  <prot>calreticulin</prot> .
PG  - 13691-6
AB  - <prot>Calnexin</prot> is an integral membrane protein that acts as a chaperone during
      glycoprotein folding in the endoplasmic reticulum. Cross-linking studies
      were carried out with the aim of investigating the interactions of
      <prot>calnexin</prot> with glycoproteins in vitro. A truncated version of the integral
      membrane glycoprotein <prot>Glut 1</prot> (<prot>GT155</prot>) was synthesized in a rabbit
      reticulocyte translation system in the presence of canine pancreatic
      microsomes. Following immunoprecipitation with an anticalnexin antiserum,
      a cross-linker-independent association was observed between  <prot>GT155</prot>  and
       <prot>calnexin</prot> . In addition, the anti-calnexin antiserum immunoprecipitated a
      UV-dependent cross-linking product consisting of  <prot>GT155</prot>  and a protein of
      approximately 60 kDa designated  <prot>CAP-60</prot>  (<prot>calnexin-associated protein</prot> of 60
      kDa). Both the  <prot>GT155</prot> - <prot>calnexin</prot>  and the  <prot>GT155</prot> - <prot>CAP-60</prot>  interactions were
      dependent on the presence of a correctly modified oligosaccharide group on
      <prot>GT155</prot>, a characteristic of many <prot>calnexin</prot> interactions. A <prot>GT155</prot> mutant that
      was not glycosylated (AGGT155) did not associate with <prot>calnexin</prot> or <prot>CAP-60</prot>.
       <prot>Calreticulin</prot> , the soluble homologue of <prot>calnexin</prot>, was also shown to
      interact with  <prot>GT155</prot>  only when the protein bore a correctly modified
      oligosaccharide group. Thus, our data show that both <prot>calnexin</prot> and
      <prot>calreticulin</prot> with <prot>Glut 1</prot> in a glycosylation-dependent manner.
AD  - School of Biological Sciences, University of Manchester, 2.205 Stopford
