TI  - Use of a two-hybrid system to investigate molecular interactions of
      <prot>GAP-43</prot>.
PG  - 195-202
AB  - We used the 'interaction trap' (two-hybrid system) to identify
      polypeptides that interact with the neuronal phosphoprotein, <prot>GAP-43</prot>, in an
      intracellular environment.  <prot>GAP-43</prot>  ( <prot>neuromodulin</prot> ,  <prot>B-50</prot> ,  <prot>F1</prot> ), a  <prot>protein
      kinase C</prot> (<prot>PKC</prot>)  substrate important for the growth and plasticity of
      neuronal connections, has been implicated in vitro in several signal
      transduction pathways. In the yeast-based cloning system, the only strong
      interaction that was detected between  <prot>GAP-43</prot>  and the <prot>calcium effector
      protein</prot>,  <prot>calmodulin</prot> (<prot>CaM</prot>) .  <prot>PKC</prot>  phosphorylates  <prot>GAP-43</prot>  on serine 41. When we
      changed this serine to an aspartate residue to mimic constitutive
      phosphorylation, the interaction with <prot>CaM</prot> was blocked. Surprisingly, the
      N-terminal third of  <prot>GAP-43</prot>  alone bound  <prot>CaM</prot>  more strongly than did intact
      <prot>GAP-43</prot>, suggesting that the protein's C-terminus may play a role in
      modulating the interaction with <prot>CaM</prot>. These results, along with other
      recent findings, suggest a novel role for the interaction between  <prot>GAP-43</prot> 
      and  <prot>CaM</prot> .
AD  - Department of Neurosurgery, Children's Hospital, Boston, MA 02115, USA.
