Co-cultured melanocytes have dendritic spine-like structures. (A) Representative image of dendritic spine-like structures (*) and filopodia (arrowheads) on co-cultured melanocyte expressing iRFPmem. (B) Illustration of spine-like structure shapes observed on co-cultured melanocyte dendrites. (C) Dimensions of spine-like structure head diameter and length. n = 20 total spine-like structures from four different skin donor derived co-cultures. (D) Percent of melanocyte dendrites with spine-like structures. n = 53 total dendrites from four co-cultures derived from different skin donors. Whiskers: 1 SD; box: 25–75%, mean. (E) The density of melanocyte dendritic spine-like structures vary from dendrite to dendrite. Whiskers: 1 SD; box: 25–75%, mean. n = 52 total dendrites from five co-cultures derived from different skin donors. (F) Co-cultured keratinocyte (eGFPmem, ker) processes interact with melanocyte (iRFPmem, mel) spine-like structures. Top right: X,Y images from asterisk in left panel. Bottom: Z, XY image from solid line in top left panel. (G and H) Some melanocyte (Mel) dendritic spines (*) have stable morphologies while interacting with adjacent keratinocytes (Ker; G), while others exhibit dynamic reshaping (<; H). Scale bars, (A) 5 µm; (F) top left, 5 µm; top right, 2 µm; bottom z axis, 1.5 µm; (G) left, 5 µm; right, 1.5 µm; (H) left, 50 µm; right, 2 µm.