Centrins control chicken cone cell lipid droplet dynamics through lipid-droplet-localized SPDL1

As evolutionarily conserved organelles, lipid droplets (LDs) carry out numerous functions and have various subcellular localizations in different cell types and species. In avian cone cells, there is a single apically localized LD. We demonstrated that CIDEA (cell death inducing DFFA like effector a) and microtubules promote the formation of the single LD in chicken cone cells. Centrins, which are well-known centriole proteins, target to the cone cell LD via their C-terminal calcium-binding domains. Centrins localize on cone cell LDs with the help of SPDL1-L (spindle apparatus coiled-coil protein 1-L), a previously uncharacterized isoform of the kinetochore-associated dynein adaptor SPDL1. The loss of CETN3 or overexpression of a truncated CETN1 abrogates the apical localization of the cone cell LD. Simulation analysis showed that multiple LDs or a single mispositioned LD reduces the light sensitivity. Collectively, our findings identify a role of centrins in the regulation of cone cell LD localization, which is important for the light sensitivity of cone cells. [Display omitted] •Centrins and microtubules regulate chicken cone cell LD dynamics•SPDL1 facilitates the localization of centrins on cone cell LDs•Centrins regulate the apical localization of LDs in cone cells•Changes in the number or position of LDs reduce the optical sensitivity of cone cells Pan et al. find that centrins localize to chicken cone cell lipid droplets with the help of SPDL1-L, a previously uncharacterized long isoform of SPDL1. Centrins and SPDL1-L regulate the apical localization of lipid droplets in cone cells.