ktub participates in light-induced rhodopsin endocytosis. Confocal images reveal rhodopsin localization in the photoreceptor cells of the wild type and ktub mutants. The flies received three hours of light stimulation and then investigated the endocytosis of rhodopsin in the photoreceptor cells. In the wild type (A), a significant amount of RLVs appeared in the cytoplasm of photoreceptor cells. In the ktub mutants (B), the majority of rhodopsin remained in the rhabdomere, with only few RLVs appearing in the cytoplasm of photoreceptor cells. Statistical analysis indicates the number of rhodopsin vesicles in the cytoplasm was significantly different in wild type and ktub mutants (three experiments, Student’s t-test *** indicating p < 0.001). The scale bar is 10 μm.