Membrane transport proteins in melanosomes: Regulation of ions for pigmentation

• Published in: Biochimica et biophysica acta. Biomembranes 2020-12, Vol.1862 (12), p.183318-183318, Article 183318
• Main Authors: Wiriyasermkul, Pattama, Moriyama, Satomi, Nagamori, Shushi
• Format: Article
• Language: English
• Subjects: Albinism, Oculocutaneous - genetics; Albinism, Oculocutaneous - pathology; Humans; Hydrogen-Ion Concentration; Ion Transport; Lysosomes - metabolism; Melanin; Melanins - biosynthesis; Melanocyte; Melanosomes - metabolism; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Monophenol Monooxygenase - genetics; Monophenol Monooxygenase - metabolism; Neutral pH; Review; Skin Pigmentation; Transporter; Tyrosinase
• ISSN: 0005-2736; 1879-2642
• DOI: 10.1016/j.bbamem.2020.183318

Melanosomes are unique organelles in melanocytes that produce melanin, the pigment for skin, hair, and eye color. Tyrosinase is the essential and rate-limiting enzyme for melanin production, that strictly requires neutral pH for activity. pH maintenance is a result of the combinational function of multiple ion transport proteins. Thus, ion homeostasis in melanosomes is crucial for melanin synthesis. Defect of the ion transport system causes various pigmentation phenotypes, from mild effect to severe disorders such as albinism. In this review, we summarize the up-to-date knowledge of the ion transport system, such as transport function, structure, and the physiological roles and mechanisms of the ion transport proteins in melanosomes. In addition, we propose a model of melanosomal ion transport system—how the functional coupling of multiple transport proteins modulates and maintains ion homeostasis. We discuss melanin synthesis in terms of the ion transport system. [Display omitted] •Melanosome is a member of lysosome-related organelles.•The neutral pH in melanosomes is critical for melanin synthesis.•Membrane transport proteins expressed in melanosomes regulate ions and pH in melanosomes.•Defect of the ion transport system causes pigmentation disorders.•Further functional studies of the transport proteins are essential to understand the mechanism of melanogenesis.