MYELIN MEMBRANE BIOGENESIS BY OLIGODENDROCYTES - DEVELOPMENTAL REGULATION OF LOW-MOLECULAR-WEIGHT GTP-BINDING PROTEINS

Oligodendrocytes synthesize dramatic amounts of myelin membrane. We hypothesized that this requires unique aspects of vesicular trafficking. Specific stages of the oligodendrocyte lineage were assayed for low molecular weight GTP-binding proteins implicated in the regulation of vesicular transport pathway (two dimensional gel electrophoresis, [alpha-P-32]GTP overlay). Consistent with the hypothesis, as oligodendrocytes differentiate from early progenitors to mature myelin-producing cells, greater than or equal to 12 small GTP-binding proteins become up-regulated. Myelin membrane also has a complex pattern of GTP-binding proteins. Several of these proteins may be specific to oligodendrocytes, suggesting that oligodendrocytes may utilize cell-type specific GTP-binding proteins for biogenesis and maintenance of the myelin membrane.