Use of a two-hybrid system to investigate molecular interactions of GAP-43.
We used the 'interaction trap' (two-hybrid system) to identify polypeptides that interact with the neuronal phosphoprotein, GAP-43, in an intracellular environment. GAP-43 (neuromodulin, B-50, F1), a protein kinase C (PKC) 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 GAP-43 and the calcium effector protein, calmodulin (CaM). PKC phosphorylates GAP-43 on serine 41. When we changed this serine to an aspartate residue to mimic constitutive phosphorylation, the interaction with CaM was blocked. Surprisingly, the N-terminal third of GAP-43 alone bound CaM more strongly than did intact GAP-43, suggesting that the protein's C-terminus may play a role in modulating the interaction with CaM. These results, along with other recent findings, suggest a novel role for the interaction between GAP-43 and CaM.
Chao
S
S
Department of Neurosurgery, Children's Hospital, Boston, MA 02115, USA.
Benowitz
L I
LI
Krainc
D
D
Irwin
N
N
D002147:Calmodulin / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002874:Chromosome Mapping; D019922:GAP-43 Protein; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism
D002147:Calmodulin; D019922:GAP-43 Protein; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins