MAG Adhesion molecule that mediates interactions between myelinating cells and neurons by binding to neuronal sialic acid-containing gangliosides and to the glycoproteins RTN4R and RTN4RL2. Not required for initial myelination, but seems to play a role in the maintenance of normal axon myelination. Protects motoneurons against apoptosis, also after injury; protection against apoptosis is probably mediated via interaction with neuronal RTN4R and RTN4RL2. Required to prevent degeneration of myelinated axons in adults; this probably depends on binding to gangliosides on the axon cell membrane. Negative regulator of neurite outgrowth; in dorsal root ganglion neurons the inhibition is mediated primarily via binding to neuronal RTN4R or RTN4RL2 and to a lesser degree via binding to neuronal gangliosides. In cerebellar granule cells the inhibition is mediated primarily via binding to neuronal gangliosides. In sensory neurons, inhibition of neurite extension depends only partially on RTN4R, RTN4RL2 and gangliosides. Inhibits axon longitudinal growth. Inhibits axon outgrowth by binding to RTN4R. Preferentially binds to alpha-2,3-linked sialic acid. Binds ganglioside Gt1b. Belongs to the immunoglobulin superfamily. SIGLEC (sialic acid binding Ig-like lectin) family. Both isoform 1 and isoform 2 are detected in myelinated structures in the central and peripheral nervous system, in periaxonal myelin and at Schmidt-Lanterman incisures (PubMed:9495552, PubMed:6200494). Detected in optic nerve, in oligodendroglia and in periaxonal myelin sheaths (PubMed:6200494). Detected in compact myelin (at protein level) (PubMed:6200494). Both isoform 1 and isoform 2 are detected in the central and peripheral nervous system (PubMed:9495552). 3 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: Cell adhesion; Membrane protein, integral
Chromosomal Location of human Ortholog: 19q13.12
Cellular Component:  compact myelin; cytoplasm; membrane raft; mesaxon; myelin sheath; myelin sheath adaxonal region; paranode region of axon; plasma membrane; Schmidt-Lanterman incisure
Molecular Function:  carbohydrate binding; ganglioside GT1b binding; protein homodimerization activity; protein kinase binding; sialic acid binding; signaling receptor binding
Biological Process:  axon regeneration; cell adhesion; cell-cell adhesion via plasma-membrane adhesion molecules; cellular response to mechanical stimulus; central nervous system myelin formation; negative regulation of axon extension; negative regulation of neuron apoptotic process; negative regulation of neuron differentiation; negative regulation of neuron projection development; positive regulation of astrocyte differentiation; positive regulation of myelination; transmission of nerve impulse
Disease: Spastic Paraplegia 75, Autosomal Recessive
Reference #:  P20916 (UniProtKB)
Alt. Names/Synonyms: GMA; MAG; myelin associated glycoprotein; Myelin-associated glycoprotein; S-MAG; sialic acid binding Ig-like lectin 4A; sialic acid-binding immunoglobulin-like lectin 4A; Siglec-4a; SIGLEC4A; SPG75
Gene Symbols: MAG
Molecular weight: 69,069 Da
Basal Isoelectric point: 4.97  Predict pI for various phosphorylation states
Protein-Specific Antibodies, siRNAs or Recombinant Proteins from Cell Signaling Technology® Total Proteins
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Protein Structure Not Found.

Cross-references to other databases:  AlphaFold  |  STRING  |  cBioPortal  |  Wikipedia  |  Reactome  |  neXtProt  |  Protein Atlas  |  BioGPS  |  Pfam  |  Phospho.ELM  |  NetworKIN  |  GeneCards  |  UniProtKB  |  Entrez-Gene  |  GenPept  |  Ensembl Gene