Skin pigmentation is dependent on a number of cellular processes including melanosome biogenesis, transport, maturation and transfer to keratinocytes. However, how the cells finely control these processes in space and time to ensure proper pigmentation remains unclear. In this work, we have shown that Dynlt3, a component of the cytoplasmic dynein complex, is required for efficient melanosome transport, acidity and transfer. In melanocytes with decreased levels of Dynlt3, pigmented melanosomes undergo a more directional motion, leading to their peripheral location in the cell. Decreased levels of Dynlt3 also result in increased acidity of stage IV, heavily pigmented, melanosomes. Melanosome transfer to neighboring keratinocytes is also decreased upon knockdown of Dynlt3. Finally, the level of Dynlt3 is dependent on β-catenin activity, revealing a novel function of the Wnt/β-catenin signalling pathway during melanocyte and skin pigmentation, by coupling the transport, positioning and acidity of melanosomes required for their transfer.

ESDR309 - Dynlt3, a novel fundamental regulator of melanosome movement, distribution, acidity and transfer

50th Annual Meeting of the European Society for Dermatological Research. VIRTUAL MEETING