1. Phosphorylation of LKB1/Par-4 establishes Schwann cell polarity to initiate and control myelin extent.
- Author
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Shen, Yun-An A, Chen, Yan, Dao, Dang Q, Mayoral, Sonia R, Wu, Laiman, Meijer, Dies, Ullian, Erik M, Chan, Jonah R, and Lu, Q Richard
- Subjects
Myelin Sheath ,Schwann Cells ,Cells ,Cultured ,Animals ,Mice ,Knockout ,Mice ,Rats ,Protein-Serine-Threonine Kinases ,Cell Adhesion Molecules ,Cell Polarity ,Amino Acid Motifs ,Phosphorylation ,Adaptor Proteins ,Signal Transducing ,Cell Cycle Proteins ,Neurosciences ,Neurodegenerative ,1.1 Normal biological development and functioning - Abstract
The Schwann cell (SC)-axon interface represents a membrane specialization that integrates axonal signals to coordinate cytoskeletal dynamics resulting in myelination. Here we show that LKB1/Par-4 is asymmetrically localized to the SC-axon interface and co-localizes with the polarity protein Par-3. Using purified SCs and myelinating cocultures, we demonstrate that localization is dependent on the phosphorylation of LKB1 at serine-431. SC-specific deletion of LKB1 significantly attenuates developmental myelination, delaying the initiation and altering the myelin extent into adulthood, resulting in a 30% reduction in the conduction velocity along the adult sciatic nerves. Phosphorylation of LKB1 by protein kinase A is essential to establish the asymmetric localization of LKB1 and Par-3 and rescues the delay in myelination observed in the SC-specific knockout of LKB1. Our findings suggest that SC polarity may coordinate multiple signalling complexes that couple SC-axon contact to the redistribution of specific membrane components necessary to initiate and control myelin extent.
- Published
- 2014