Summary of phenotypic effects of GAP-43 mutations
| Mutation | Functional consequences | |
|---|---|---|
| G19 | Ser 41 → Gly | Cannot be phosphorylated by PKC |
| (equivalent to Ser 41 → Ala) | Binds calmodulin constitutively | |
| Enlarged endosomes | ||
| Deficient in depolarized-induced FM1-43 fluorescence | ||
| CAM | Delete calmodulin | Cannot bind calmodulin |
| binding domain | Smaller endosomes | |
| Enhancement of depolarization-induced FM1-43 fluorescence | ||
| Asp | Ser 41 → Asp | Mimics phosphorylation of Ser 41 by PKC |
| Cannot bind calmodulin | ||
| Enhancement of depolarization-induced FM1-43 fluorescence | ||
| Greater depletion of FM1-43 fluorescence after second high-K+treatment |