myelin assembly

Definition

Target type: biologicalprocess

The process in which the wraps of cell membrane that constitute myelin are laid down around an axon in the central or peripheral nervous system. [GOC:dgh, GOC:dph, GOC:tb]

Myelin assembly is a complex and tightly regulated process that involves the formation of myelin sheaths around axons, providing insulation and facilitating rapid nerve impulse conduction. It begins with the commitment of oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS) to myelination. These glial cells express specific transcription factors and signaling molecules that initiate the process.

The initial step involves the extension of processes from the oligodendrocytes or Schwann cells, wrapping around the axon in a spiral fashion. This wrapping forms the myelin sheath, which consists of multiple layers of compacted plasma membrane. The process is guided by cues from the axon, including the expression of specific adhesion molecules.

As the myelin sheath forms, the glial cell cytoplasm is gradually excluded, leaving behind compact layers of membrane. The myelin sheath is composed primarily of lipids, including cholesterol, phospholipids, and sphingolipids, which provide its insulating properties. Myelin also contains proteins, such as myelin basic protein (MBP), proteolipid protein (PLP), and myelin-associated glycoprotein (MAG), which play critical roles in maintaining the integrity and stability of the sheath.

During myelin assembly, the glial cell membrane undergoes extensive remodeling and compaction. This process involves the formation of specialized junctions between adjacent layers of membrane, known as compact myelin. These junctions are critical for maintaining the structural integrity of the myelin sheath.

Myelin assembly is a dynamic process that continues throughout life. The myelin sheath is constantly remodeled and repaired in response to changes in neuronal activity and environmental cues. Disruptions in myelin assembly can lead to a variety of neurological disorders, including multiple sclerosis, leukodystrophies, and Charcot-Marie-Tooth disease.'
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Proteins (3)

Compounds (7)