FIGURE 9.

Rab3 and RabX2 are important components of TRPL recycling. In the dark, TRPL is localized to the rhabdomeric membrane and translocates to the endosomal network within 2 h after light adaptation. From there, it is transported to the ER within 12 h, where it is temporarily stored. Upon renewed dark adaptation, TRPL is transported from the ER via the trans-Golgi network back to the rhabdomeric membrane within 90 min. Anterograde transport due to de novo synthesis of TRPL occurs via the cis- and trans-Golgi networks (green arrows). A small fraction of internalized TRPL is degraded via the lysosomal degradation pathway (red arrows). Rab3 was identified at the late endosome and is essential for TRPL transport to the ER as well as for proper recycling (burgundy). In contrast, knock-out of RabX2 resulted in accumulation of TRPL at the trans-Golgi (magenta). Marker proteins for the different membrane enclosed compartments are indicated by dots (turquoise).