Researchers at the University of Pennsylvania School of Medicine have discovered how a protein called Pmel17 is sorted by pigment cells in the skin and eye to make a fiber matrix that eventually sequesters melanin, the dark pigment found in skin, hair, and eyes. Understanding the molecular steps prior to fiber formation – and when this process goes awry – may lead to a better understanding of melanoma and Alzheimer’s disease. Pmel17 is a major target within the immune system in current anti-melanoma immunotherapies. Michael S. Marks, PhD, Associate Professor of Pathology and Laboratory Medicine, and colleagues published their findings in the March issue of Developmental Cell.