MAG

Protein identityUniProt · HPA

UniProt accession

P20916

Gene

MAG

Ensembl

ENSG00000105695

Chromosome

19

Canonical length

626 aa

Protein class

Disease related genes, Human disease related genes, Plasma proteins, Predicted intracellular proteins, Predicted membrane proteins

Subcellular location

Equatorial segment,Perinuclear theca

Quaternary structure

Homodimer

OverviewNCBI Gene

The protein encoded by this gene is a type I membrane protein and member of the immunoglobulin superfamily. It is thought to be involved in the process of myelination. It is a lectin that binds to sialylated glycoconjugates and mediates certain myelin-neuron cell-cell interactions. Three alternatively spliced transcripts encoding different isoforms have been described for this gene. [provided by RefSeq, Nov 2010]

Canonical amino-acid sequenceUniProt

626 residues, UniProt reviewed canonical sequence.

>P20916|MAG
     1  MIFLTALPLF WIMISASRGG HWGAWMPSSI SAFEGTCVSI PCRFDFPDEL RPAVVHGVWY
    61  FNSPYPKNYP PVVFKSRTQV VHESFQGRSR LLGDLGLRNC TLLLSNVSPE LGGKYYFRGD
   121  LGGYNQYTFS EHSVLDIVNT PNIVVPPEVV AGTEVEVSCM VPDNCPELRP ELSWLGHEGL
   181  GEPAVLGRLR EDEGTWVQVS LLHFVPTREA NGHRLGCQAS FPNTTLQFEG YASMDVKYPP
   241  VIVEMNSSVE AIEGSHVSLL CGADSNPPPL LTWMRDGTVL REAVAESLLL ELEEVTPAED
   301  GVYACLAENA YGQDNRTVGL SVMYAPWKPT VNGTMVAVEG ETVSILCSTQ SNPDPILTIF
   361  KEKQILSTVI YESELQLELP AVSPEDDGEY WCVAENQYGQ RATAFNLSVE FAPVLLLESH
   421  CAAARDTVQC LCVVKSNPEP SVAFELPSRN VTVNESEREF VYSERSGLVL TSILTLRGQA
   481  QAPPRVICTA RNLYGAKSLE LPFQGAHRLM WAKIGPVGAV VAFAILIAIV CYITQTRRKK
   541  NVTESPSFSA GDNPPVLFSS DFRISGAPEK YESERRLGSE RRLLGLRGEP PELDLSYSHS
   601  DLGKRPTKDS YTLTEELAEY AEIRVK

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against MAG can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability

Cell surface

Secreted

No

Transmembrane segments

1

Mean surface accessibility (rSASA)

0.38

Highest tissue expression

700 nTPM

Expression across tissuesHPA

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about MAG.

Disease | AllUniProt

Conditions MAG is implicated in, by any mechanism.

• Spastic paraplegia 75, autosomal recessive (SPG75) MIM:616680

Disease | GeneticClinVar

16 pathogenic / likely-pathogenic of 371 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

• Hereditary spastic paraplegia 75
• Orofacial cleft 1

Disease | ImmuneIEDB

Conditions an epitope on MAG was assayed in.

• multiple sclerosis B and T cell

Disease | AutoantibodyPubMed

Conditions in which antibodies against MAG are reported. Each links to that disease's full target list.

• Paraproteinemias 16
• Polyneuropathies 16
• Peripheral Nervous System Diseases 15
• Polyradiculoneuropathy, Chronic Inflammatory Demyelinating 10
• Polyradiculoneuropathy 6

Showing 5 of 7 — disease pages carrying at least 10 antigens.

ReferencesPubMed · IEDB

Publications for MAG from three distinct lines of evidence, kept separate because they answer different questions: whether antibodies are directed at the protein, whether a B-cell epitope has been mapped on it, and whether a T-cell epitope has. Each is labelled with its source.

Sources: PubMed — antigen-level antibody evidence from a custom retrieval. Records matching a controlled set of autoantibody terms (the MeSH descriptors Autoantibodies and Autoantigens, with title and abstract term variants) were obtained through NCBI E-utilities, and their titles and abstracts parsed for constructions that direct an antibody at a named protein rather than for co-occurrence. Captured names were resolved against UniProt nomenclature and each antigen adjudicated individually against the source text. IEDB — curated epitope assays from the Immune Epitope Database (Vita et al., Nucleic Acids Research 2019). Bibliographic records from PubMed and MeSH, U.S. National Library of Medicine; citation metrics from NIH iCite (Hutchins et al., PLoS Biology 2016). Titles link to PubMed; abstracts are not reproduced here. The NLM does not endorse this analysis.

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)

0.42

gnomAD pLI

0.49

gnomAD missense Z

1.13

DepMap mean gene effect

-0.06

DepMap dependency class

selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

• 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
• substantia nigra development
• transmission of nerve impulse

Molecular functions

• carbohydrate binding
• ganglioside GT1b binding
• protein homodimerization activity
• protein kinase binding
• sialic acid binding
• signaling receptor binding

Cellular components

• compact myelin
• membrane raft
• mesaxon
• myelin sheath
• myelin sheath adaxonal region
• paranode region of axon
• plasma membrane
• Schmidt-Lanterman incisure

Protein domainsUniProt · Pfam · InterPro

• Immunoglobulin subtype 2
• Immunoglobulin domain subtype
• Immunoglobulin-like domain
• CD80-like, immunoglobulin C2-set
• Immunoglobulin-like fold
• Immunoglobulin-like domain superfamily
• Sialic acid-binding Ig-like lectin
• CD80-like C2-set immunoglobulin domain
• Immunoglobulin domain

KeywordsUniProt

• Cell adhesion
• Cell membrane
• Disulfide bond
• Glycoprotein
• Hereditary spastic paraplegia
• Immunoglobulin domain
• Lectin
• Lipid-binding
• Lipoprotein
• Membrane
• Neurodegeneration
• Palmitate
• Phosphoprotein
• Repeat
• Signal
• Transmembrane
• Transmembrane helix
• Ubl conjugation

InteractionsUniProt · HPA

Protein binding partners of MAG in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

• RTN4R
• RTN4RL2
• BSG