The major goals of our research are to gain a better understanding of the biogenesis and functions of specialized endosomal organelles: the lysosome-related organelles of pigment cells called melanosomes and exosomes, which are secreted from multivesicular bodies. One focus is on elucidating mechanisms involved in early melanogenesis in particular those underlying the generation of physiological amyloids (sorting and processing mechanisms). Another aspect addresses how genes mutated in lysosomal diseases (Hermansky Pudlak Syndrom) regulate late stages of melanogenesis and how these novel trafficking regulators operate in concert with other ubiquitous components of the trafficking machinery (adaptors, Kinesins, Myosins, Rab GTPases and effectors). Our projects aim at over passing the current knowledge on the cellular and molecular basis of melanosome dysfunction in pigmentation related disorders and melanoma and the role of exosomes in pigmentation and amyloidogenesis. These studies will also contribute to enlighten generalized structural and functional modifications of the endosomal system in specialized cells. They aim at shedding light onto the molecular machinery that controls endosomal sorting and motility and the mechanisms underlying cellular communications within the epidermal-melanin unit by direct cell-cell contacts or via secretion of exosomes.