Loss of ktub blocked norpA -mediated rhodopsin endocytosis. Confocal images show the ability of rhodopsin endocytosis in wild type (A), norpA33 (B) and norpA33/ktub115-4double mutants (C). Flies were reared in the dark and then followed by light exposure (500 lux) for 24 hours. After light exposure, some RLVs were detected in the cytoplasm of the wild type photoreceptor cells (A). The norpA33 mutants exhibited massive RLVs in the cytoplasm of photoreceptor cells (B). However, the massive RLVs were rescued by loss of ktub in norpA33 mutants (C). A, B and C were stained with Anti-Rh1antibody (green), and A’, B’ and C’ were stained with rhodamine-phalloidin (red).