Compact myelin, the paranode, and the juxtaparanode are discrete domains that are formed on myelinated axons. In humans, neurological disorders associated with loss of myelin, including Multiple Sclerosis, often also result in disassembly of the node of Ranvier. Despite the importance of these domains in the proper functioning of the CNS, their molecular composition and assembly mechanism remains largely unknown. We therefore performed a large-scale proteomics MudPIT screen for the identification of proteins in human myelin and axogliasomal fractions. We identified over 1,000 proteins in these fractions. Since even minor perturbations in neuron-glial interactions can uncouple the glial support of axons, the proteome map presented here can be used as a reference library for "myelin health" and disease states, including white matter disorders such as leukodystrophies and multiple sclerosis. (C) 2010 Wiley-Liss, Inc.