Melanocytes act as the sensory and regulatory cells of the skin with the computing capabilities. MC, melanocytes; KC, keratinocytes; LC, Langerhans cells; Ly, lymphocytes; Mast C, mast cells; MAC, macrophages; Fb, fibroblasts; EC, endothelial cells; DD, dermal dendritic cells; ⊙, melanosomes; →, direction of melanosomes movement/transfer,; =:, gap junctions; (): flow of ions and micromolecules. Reprinted with modifications from the J Theor Biol 1993: 164: 103–120, with permission from the Elsevier).