The Journal of Neuroscience, May 13, 2009, 29(19):6094-6104; doi:10.1523/JNEUROSCI.0686-09.2009
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Development/Plasticity/Repair
Cholesterol Regulates the Endoplasmic Reticulum Exit of the Major Membrane Protein P0 Required for Peripheral Myelin Compaction
Gesine Saher,1 *
Susanne Quintes,1 *
Wiebke Möbius,1
Michael C. Wehr,1
Eva-Maria Krämer-Albers,2
Britta Brügger,3 and
Klaus-Armin Nave1
1Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Goettingen, Germany, 2Department of Biology, Unit of Molecular Cell Biology, Mainz University, 55099 Mainz, Germany, and 3Heidelberg University Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
Correspondence should be addressed to either Dr. Gesine Saher or Dr. Klaus-Armin Nave, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Goettingen, Germany, Email: saher{at}em.mpg.de or Email: nave{at}em.mpg.de
Rapid impulse conduction requires electrical insulation of axons by myelin, a cholesterol-rich extension of the glial cell membrane with a characteristic composition of proteins and lipids. Mutations in several myelin protein genes cause endoplasmic reticulum (ER) retention and disease, presumably attributable to failure of misfolded proteins to pass the ER quality control. Because many myelin proteins partition into cholesterol-rich membrane rafts, their interaction with cholesterol could potentially be part of the ER quality control system. Here, we provide in vitro and in vivo evidence that the major peripheral myelin protein P0 requires cholesterol for exiting the ER and reaching the myelin compartment. Cholesterol dependency of P0 trafficking in heterologous cells is mediated by a cholesterol recognition/interaction amino acid consensus (CRAC) motif. Mutant mice lacking cholesterol biosynthesis in Schwann cells suffer from severe hypomyelination with numerous uncompacted myelin stretches. This demonstrates that high-level cholesterol coordinates P0 export with myelin membrane synthesis, which is required for the correct stoichiometry of myelin components and for myelin compaction.
Received Feb. 10, 2009;
accepted March 22, 2009.
Correspondence should be addressed to either Dr. Gesine Saher or Dr. Klaus-Armin Nave, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Goettingen, Germany, Email: saher{at}em.mpg.de or Email: nave{at}em.mpg.de