The myelin protein MAL affects peripheral nerve myelination: a new player influencing p75 neurotrophin receptor expression.
The myelin and lymphocyte protein (MAL) is a raft-associated membrane protein predominantly expressed by oligodendrocytes and Schwann cells. Here we show that MAL regulates myelination in the peripheral nervous system. In mice overexpressing MAL, myelination was retarded and fibers were hypomyelinated, whereas myelination in MAL knockout mice was accelerated. This was not due to impaired Schwann cell proliferation, differentiation or axonal sorting. We found that the expression level of p75 neurotrophin receptor mRNA and protein was strongly reduced in developing sciatic nerves in MAL-overexpressing mice. This reduction is well correlated with the observed alterations in myelination initiation, speed of myelination and alterations in Remak bundle development. Our results suggest a functional role for MAL in peripheral myelination by influencing the expression of membrane components that mediate axon-glia interaction during ensheathment and myelin wrapping.
Buser
A M
AM
Neurobiology, Department of Biomedicine and Neurology, University Hospital Basel, Basel, Switzerland.
Schmid
D
D
Kern
F
F
Erne
B
B
Lazzati
T
T
Schaeren-Wiemers
N
N
D000818:Animals; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D021962:Membrane Microdomains / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D009185:Myelin Proteins / Q000235:genetics / Q000378:metabolism*; D009186:Myelin Sheath / Q000378:metabolism* / Q000648:ultrastructure; D062806:Myelin and Lymphocyte-Associated Proteolipid Proteins; D009413:Nerve Fibers, Myelinated / Q000378:metabolism* / Q000648:ultrastructure; D010525:Peripheral Nerves / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D011510:Proteolipids / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020800:Receptor, Nerve Growth Factor / Q000235:genetics / Q000378:metabolism*; D012583:Schwann Cells / Q000378:metabolism
C569027:Mal protein, mouse; D026901:Membrane Transport Proteins; D009185:Myelin Proteins; D062806:Myelin and Lymphocyte-Associated Proteolipid Proteins; D011510:Proteolipids; D012333:RNA, Messenger; D020800:Receptor, Nerve Growth Factor