5lfu
From Proteopedia
Myelin-associated glycoprotein (MAG) glycosylated and lysine-methylated full extracellular domain
Structural highlights
FunctionMAG_MOUSE Adhesion molecule in postnatal neural development that mediates sialic-acid dependent cell-cell interactions between neuronal and myelinating cells. Preferentially binds to alpha-2,3-linked sialic acid. Isoform L-MAG is critical for the formation of myelin in the CNS, whereas isoform S-MAG is sufficient to maintain the integrity of myelin in PNS.[1] Publication Abstract from PubMedMyelin-associated glycoprotein (MAG) is a myelin-expressed cell-adhesion and bi-directional signalling molecule. MAG maintains the myelin-axon spacing by interacting with specific neuronal glycolipids (gangliosides), inhibits axon regeneration and controls myelin formation. The mechanisms underlying MAG adhesion and signalling are unresolved. We present crystal structures of the MAG full ectodomain, which reveal an extended conformation of five Ig domains and a homodimeric arrangement involving membrane-proximal domains Ig4 and Ig5. MAG-oligosaccharide complex structures and biophysical assays show how MAG engages axonal gangliosides at domain Ig1. Two post-translational modifications were identified-N-linked glycosylation at the dimerization interface and tryptophan C-mannosylation proximal to the ganglioside binding site-that appear to have regulatory functions. Structure-guided mutations and neurite outgrowth assays demonstrate MAG dimerization and carbohydrate recognition are essential for its regeneration-inhibiting properties. The combination of trans ganglioside binding and cis homodimerization explains how MAG maintains the myelin-axon spacing and provides a mechanism for MAG-mediated bi-directional signalling. Structural basis of myelin-associated glycoprotein adhesion and signalling.,Pronker MF, Lemstra S, Snijder J, Heck AJ, Thies-Weesie DM, Pasterkamp RJ, Janssen BJ Nat Commun. 2016 Dec 6;7:13584. doi: 10.1038/ncomms13584. PMID:27922006[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
|