Updated project metadata. Here we present the data obtained from a high precision 18O-labeling strategy used to quantitatively map membrane proteins isolated from myelin-enriched fractions purified from distinct brain regions of an adult mouse. To this end, we present an updated catalog of myelin-associated proteins found in the vertebrate CNS with relevance for investigations of myelin disorders. We also present a number of regiospecific protein markers of the brain, many of which remain unannotated in current online brain mapping databases.