RAC1 and retinal disorder: Among the nine APLP2-specific interactors identified in the brain [82], four are of potential interest because of their involvement in retinal development or retinal disorder: Retinitis Pigmentosa 2 homolog (RP2h), Ras-related C3 botulinum substrate 1 (RAC1), Protein phosphatase 2A (PP2A) and Rho family GTPase (RhoA).