Melanosome

A melanosome is a specialized, membrane-bound organelle found in animal cells, primarily melanocytes and retinal pigment epithelial cells, responsible for the synthesis, storage, and transport of melanin pigments (Wikipedia, 2024). It is classified as a lysosome-related organelle (LRO) due to its shared structural and functional characteristics with lysosomes, including an acidic lumen and specific membrane proteins (PubMed: 11740387). The primary biological function of the melanosome is to provide photoprotection by sequestering melanin, which absorbs and scatters harmful ultraviolet radiation to prevent DNA damage in the skin (NIH, 2023). Dysregulation of melanosome biogenesis, maturation, or transport is linked to various genetic and acquired disorders, such as oculocutaneous albinism, vitiligo, and Hermansky-Pudlak syndrome (PubMed: 24507544). In oncology, melanosome-associated proteins like gp100 and MART-1 serve as critical biomarkers for the diagnosis and targeted immunotherapy of melanoma (PubMed: 15150593). While the melanosome itself is an organelle rather than a single molecular target, it serves as the site of action for many dermatological drugs, such as hydroquinone, which inhibits the enzyme tyrosinase within the organelle to reduce pigmentation (StatPearls, 2023).

Other names

Pigment granuleMelanin granule

Inhibition of tyrosinase activity within the organelle, disruption of melanosome maturation, or inhibition of melanosome transfer to keratinocytes (StatPearls, 2023; PubMed: 24507544).