TI  - Interaction of the protein  <prot>nucleobindin</prot>  with  <prot>G alpha i2</prot> , as revealed by
      the yeast two-hybrid system.
PG  - 155-8
AB  - The heterotrimeric G protein, <prot>G alpha i2</prot>, transduces signals from seven
      membrane spanning receptors to effectors such as adenylyl cyclase and ion
      channels. The purpose of this study was to identify these or other
      cellular proteins that interact with <prot>G alpha i2</prot> by use of the yeast
      two-hybrid system. A human B cell cDNA library was screened by this system
      using full length <prot>G alpha i2</prot>. Four positive colonies were obtained. Two of
      the four were identified as <prot>nucleobindin</prot>, a calcium binding protein and a
      putative antigen to which anti-nuclear antibodies are generated in mice
      with a disorder that resembles systemic lupus erythematosus. <prot>Nucleobindin</prot>
      has a leucine zipper, EF hands, and a signal peptide sequence and is
      thought to localize to the nucleus as well as being secreted. The
      specificity of intehraction between  <prot>G alpha i2</prot>  and  <prot>nucleobindin</prot>  was
      confirmed by an in vitro binding assay using recombinant proteins.
      Transfection of <prot>G alpha i2</prot> and <prot>nucleobindin</prot> in COS cells increased <prot>G alpha
      i2</prot> expression relative to cells transfected with <prot>G alpha i2</prot> and mock
      vector. Our results indicate that the yeast two-hybrid system provides a
      means to identify novel proteins that interact with  G alpha proteins .
       <prot>Nucleobindin</prot>  appears to represent one of those proteins.
AD  - Department of Pharmacology, University of California San Diego, La Jolla
