Skin pigmentation is dependent on 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. Here, we show that a component of the cytoplasmic dynein complex, Dynlt3, is required for efficient melanosome transport, maturation and transfer. In melanocytes with decreased levels of Dynlt3, pigmented melanosomes undergo a more directional (convective) motion leading to their peripheral location in the cell, and are not fully matured. Stage IV melanosomes are more acidic, but still heavily pigmented, resulting in a less efficient melanosome transfer. 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, position and maturation of melanosomes required for their transfer.

中文翻译：

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Dynlt3，一种新型的黑色素体运动，分布，成熟和转移的基本调节剂

皮肤色素沉着取决于细胞过程，包括黑素体的生物发生，运输，成熟和转移到角质形成细胞。然而，细胞如何精确地控制这些过程在空间和时间上以确保适当的色素沉着还不清楚。在这里，我们表明，有效的黑素体运输，成熟和转移需要细胞质动力蛋白复合物Dynlt3的组成部分。在具有降低的Dynlt3水平的黑素细胞中，有色的黑素体经历了更多的定向（对流）运动，从而导致它们在细胞中的外围位置，并且尚未完全成熟。IV期黑素体酸性更高，但色素沉着，导致黑素体转移效率降低。最后，Dynlt3的水平取决于β-catenin的活性，