Figure 1. Autophagy activation correlates with melanogenesis in melanocytic nevi.

(a) LC3 expression coincides with melanogenesis in sun-exposed skin of Korean patients. Immunohistochemical (top) or immunofluorescence staining (bottom) with anti-LC3 antibody (green) and anti-MART1 (melan A; red) antibody was performed to determine the extent to which LC3 expression is associated with melanin pigment in sun-exposed skin. The inset box represents an area shown at higher magnification (1000×). Magnification, 400×; Scale bar, 200 μm. (b–d) The relationship between autophagy flow and melanin synthesis in Melan-a melanocytes in the presence or absence of autophagy activator rapamycin (Rap) at indicated concentration for 24 h was determined by detecting conversion of LC3-I to LC3-II and p62 degradation using Western blot analysis. A subset of cells was also exposed to the lysosomal inhibitor bafilomycin A1 (Baf.A). Protein expression was determined via quantitative densitometry of experimental proteins compared to β-actin expression (b,c), and melanogenesis was estimated by measuring melanin content (d) compared to control cells. *P < 0.05 versus untreated controls. N.S., not significant.