RT Journal Article
SR Electronic
T1 GAP-43 amino terminal peptides modulate growth cone morphology and neurite outgrowth
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 5503
OP 5513
DO 10.1523/JNEUROSCI.14-09-05503.1994
VO 14
IS 9
A1 SM Strittmatter
A1 M Igarashi
A1 MC Fishman
YR 1994
UL http://www.jneurosci.org/content/14/9/5503.abstract
AB The neuronal growth-associated protein GAP-43 is expressed maximally during development and regeneration, and is enriched at the cytosolic surface of the growth cone membrane. GAP-43 can activate the GTP- binding protein G(o) which is also a major component of the growth cone membrane. These findings have led to the hypothesis that GAP-43 might modulate neurite outgrowth by altering G-protein activity. Here we define the sequence requirements for GAP-43 amino terminal peptide stimulation of G(o), and test these peptides as potential modulators of neurite outgrowth. The first 10 amino acids of GAP-43, Met-Leu-Cys-Cys- Met-Arg-Arg-Thr-Lys-Gln, stimulate G(o). Substitutions at particular residues reveal that cys3, cys4, arg6, and lys9 are critical, but arg7 is not. Both the GAP-43(1–10) peptide and the G-protein-activating peptide mastoparan induce growth cone collapse and inhibit neurite extension from embryonic chick dorsal root ganglion and retinal neurons. This is likely to be mediated by G-proteins: pertussis toxin blocks the inhibition, and mutant peptides that do not activate G(o) do not alter outgrowth. In contrast to the case with embryonic chick dorsal root ganglion cells, neurite outgrowth from N1E-115 neuroblastoma cells is stimulated by GAP-43(1–10). This is probably also a G-protein-mediated event because it is blocked by pertussis toxin, because the sequence requirements match those for G(o) stimulation, and because mastoparan stimulates outgrowth from these cells. The longer GAP-43(1–25) peptide does not alter neurite outgrowth unless the cells are permeabilized, suggesting an intracellular site of action. These data identify a novel set of compounds that modulate neurite outgrowth, and also support the notion that GAP-43 can alter neurite extension by modulating pertussis toxin-sensitive G-protein activity in the growth cone.