Neuregulin-1 type III determines the ensheathment fate of axons.

摘要: The signals that determine whether axons are ensheathed or myelinated by Schwann cells have long been elusive. We now report threshold levels of neuregulin-1 (NRG1) type III on their ensheathment fate. Ensheathed express low whereas fibers high NRG1 III. Sensory neurons from deficient mice poorly and fail to myelinate; lentiviral-mediated expression rescues these defects. Expression also converts the normally unmyelinated sympathetic myelination. Nerve haploinsufficient for disproportionately unmyelinated, aberrantly ensheathed, hypomyelinated, with reduced conduction velocities. Type is sole isoform retained at axon surface activates PI 3-kinase, which required cell These results indicate III, independent diameter, provide a key instructive signal determines fate axons.