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Protein

Myelin-associated glycoprotein

Gene

Mag

Organism
Rattus norvegicus (Rat)
Status
Reviewed-Annotation score: -Experimental evidence at protein leveli

Functioni

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 (PubMed:8995428, PubMed:9298990). 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 (By similarity). 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 (PubMed:17640868). In cerebellar granule cells the inhibition is mediated primarily via binding to neuronal gangliosides (PubMed:17640868). In sensory neurons, inhibition of neurite extension depends only partially on RTN4R, RTN4RL2 and gangliosides (PubMed:19367338). Inhibits axon longitudinal growth (PubMed:9298990). Inhibits axon outgrowth by binding to RTN4R (By similarity). Preferentially binds to alpha-2,3-linked sialic acid (PubMed:8995428). Binds ganglioside Gt1b (PubMed:8995428).By similarity4 Publications

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Binding sitei118Ganglioside GT1bBy similarity1

GO - Molecular functioni

  • carbohydrate binding Source: UniProtKB-KW
  • ganglioside GT1b binding Source: UniProtKB
  • protein homodimerization activity Source: RGD
  • protein kinase binding Source: RGD
  • receptor binding Source: RGD
  • sialic acid binding Source: UniProtKB

GO - Biological processi

  • cell adhesion Source: UniProtKB
  • cell-cell adhesion via plasma-membrane adhesion molecules Source: UniProtKB
  • cellular response to mechanical stimulus Source: RGD
  • central nervous system myelination Source: RGD
  • negative regulation of axon extension Source: UniProtKB
  • negative regulation of neuron apoptotic process Source: UniProtKB
  • negative regulation of neuron differentiation Source: RGD
  • negative regulation of neuron projection development Source: RGD
  • nervous system development Source: RGD
  • positive regulation of astrocyte differentiation Source: RGD
  • positive regulation of myelination Source: RGD
  • substantia nigra development Source: RGD

Keywordsi

Biological processCell adhesion
LigandLectin, Lipid-binding

Enzyme and pathway databases

ReactomeiR-RNO-193634 Axonal growth inhibition (RHOA activation)
R-RNO-210991 Basigin interactions

Names & Taxonomyi

Protein namesi
Recommended name:
Myelin-associated glycoprotein
Alternative name(s):
1B2362 Publications
Brain neuron cytoplasmic protein 3
Sialic acid-binding Ig-like lectin 4a
Short name:
Siglec-4a
Gene namesi
Name:Mag
OrganismiRattus norvegicus (Rat)
Taxonomic identifieri10116 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresGliresRodentiaMyomorphaMuroideaMuridaeMurinaeRattus
Proteomesi
  • UP000002494 Componenti: Chromosome 1

Organism-specific databases

RGDi3035 Mag

Subcellular locationi

Extracellular region or secreted Cytosol Plasma membrane Cytoskeleton Lysosome Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertionGraphics by Christian Stolte; Source: COMPARTMENTS

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini20 – 516ExtracellularSequence analysisAdd BLAST497
Transmembranei517 – 536HelicalSequence analysisAdd BLAST20
Topological domaini537 – 626CytoplasmicSequence analysisAdd BLAST90

Keywords - Cellular componenti

Cell membrane, Membrane

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi118R → A or D: Abolishes inhibition of neurite outgrowth from CNS neurons. 1 Publication1
Mutagenesisi118R → A: No effect on inhibition of neurite outgrowth from sensory neurons. 1 Publication1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Signal peptidei1 – 19Add BLAST19
ChainiPRO_000001485820 – 626Myelin-associated glycoproteinAdd BLAST607

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Disulfide bondi37 ↔ 1651 Publication
Disulfide bondi42 ↔ 1001 Publication
Glycosylationi99N-linked (GlcNAc...) asparagineSequence analysis1
Disulfide bondi159 ↔ 2171 Publication
Glycosylationi223N-linked (GlcNAc...) asparagineSequence analysis1
Glycosylationi246N-linked (GlcNAc...) asparagineSequence analysis1
Disulfide bondi261 ↔ 3051 Publication
Glycosylationi315N-linked (GlcNAc...) asparagineSequence analysis1
Glycosylationi332N-linked (GlcNAc...) asparagineSequence analysis1
Disulfide bondi347 ↔ 3921 Publication
Glycosylationi406N-linked (GlcNAc...) asparagineSequence analysis1
Disulfide bondi421 ↔ 4301 Publication
Disulfide bondi432 ↔ 4881 Publication
Glycosylationi450N-linked (GlcNAc...) asparagineSequence analysis1
Glycosylationi454N-linked (GlcNAc...) asparagineSequence analysis1
Lipidationi531S-palmitoyl cysteine1 Publication1
Modified residuei545PhosphoserineCombined sources1
Modified residuei547PhosphoserineCombined sources1
Modified residuei549PhosphoserineCombined sources1

Post-translational modificationi

N-glycosylated.By similarity
Phosphorylated on tyrosine residues.1 Publication

Keywords - PTMi

Disulfide bond, Glycoprotein, Lipoprotein, Palmitate, Phosphoprotein

Proteomic databases

PaxDbiP07722
PRIDEiP07722

PTM databases

iPTMnetiP07722
PhosphoSitePlusiP07722

Expressioni

Tissue specificityi

Detected in myelin (PubMed:17640868). Detected in olfactory bulb and throughout the brain (at protein level) (PubMed:4020419). Detected in brain (PubMed:2432614).2 Publications

Gene expression databases

BgeeiENSRNOG00000021023
ExpressionAtlasiP07722 baseline and differential
GenevisibleiP07722 RN

Interactioni

Subunit structurei

Monomer and homodimer (By similarity). Interacts (via the first three N-terminal Ig-like domains) with RTN4R and RTN4RL2 (PubMed:19420245).By similarity1 Publication

GO - Molecular functioni

  • protein homodimerization activity Source: RGD
  • protein kinase binding Source: RGD
  • receptor binding Source: RGD

Protein-protein interaction databases

BioGridi2480591 interactor.
STRINGi10116.ENSRNOP00000028544

Structurei

3D structure databases

ProteinModelPortaliP07722
SMRiP07722
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini22 – 120Ig-like V-typeAdd BLAST99
Domaini139 – 237Ig-like C2-type 1Add BLAST99
Domaini241 – 325Ig-like C2-type 2Add BLAST85
Domaini327 – 412Ig-like C2-type 3Add BLAST86
Domaini413 – 508Ig-like C2-type 4Add BLAST96

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni20 – 325Interaction with RTN4R and RTN4RL21 PublicationAdd BLAST306
Regioni65 – 67Ganglioside GT1b bindingBy similarity3
Regioni124 – 128Ganglioside GT1b bindingBy similarity5
Regioni577 – 626Required for normal axon myelination in the central nervous systemBy similarityAdd BLAST50

Domaini

The C-terminal cytoplasmic region found only in isoform L-MAG is required for normal myelination in the central nervous system (CNS), but is apparently not required for normal myelination in the peripheral nervous system (PNS).By similarity
The extracellular domain is required to protect against axon degeneration (By similarity). The first three Ig-like domains mediate interaction with RTN4R and RTN4RL2, but are not sufficient to inhibit neurite outgrowth (PubMed:19420245). The two C-terminal extracellular Ig-like C2-type domains are required for inhibition of axon longitudinal growth (PubMed:9298990, PubMed:19420245, PubMed:19367338). Besides, the two C-terminal extracellular Ig-like C2-type domains are required for protection against apoptosis after nerve injury (By similarity).By similarity3 Publications

Sequence similaritiesi

Keywords - Domaini

Immunoglobulin domain, Repeat, Signal, Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiENOG410IUGJ Eukaryota
ENOG410XQVV LUCA
GeneTreeiENSGT00760000119139
HOGENOMiHOG000113464
HOVERGENiHBG006317
InParanoidiP07722
KOiK06771
OMAiWYFNSPY
OrthoDBiEOG091G03Q5
PhylomeDBiP07722
TreeFamiTF332441

Family and domain databases

Gene3Di2.60.40.104 hits
InterProiView protein in InterPro
IPR013162 CD80_C2-set
IPR007110 Ig-like_dom
IPR036179 Ig-like_dom_sf
IPR013783 Ig-like_fold
IPR003599 Ig_sub
IPR003598 Ig_sub2
PfamiView protein in Pfam
PF08205 C2-set_2, 1 hit
SMARTiView protein in SMART
SM00409 IG, 4 hits
SM00408 IGc2, 2 hits
SUPFAMiSSF48726 SSF48726, 4 hits
PROSITEiView protein in PROSITE
PS50835 IG_LIKE, 2 hits

Sequences (2)i

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

This entry describes 2 isoformsi produced by alternative splicing. AlignAdd to basket

Isoform L-MAG (identifier: P07722-1) [UniParc]FASTAAdd to basket

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

« Hide

        10         20         30         40         50
MIFLTTLPLF WIMISASRGG HWGAWMPSSI SAFEGTCVSI PCRFDFPDEL
60 70 80 90 100
RPAVVHGVWY FNSPYPKNYP PVVFKSRTQV VHESFQGRSR LLGDLGLRNC
110 120 130 140 150
TLLLSTLSPE LGGKYYFRGD LGGYNQYTFS EHSVLDIINT PNIVVPPEVV
160 170 180 190 200
AGTEVEVSCM VPDNCPELRP ELSWLGHEGL GEPTVLGRLR EDEGTWVQVS
210 220 230 240 250
LLHFVPTREA NGHRLGCQAA FPNTTLQFEG YASLDVKYPP VIVEMNSSVE
260 270 280 290 300
AIEGSHVSLL CGADSNPPPL LTWMRDGMVL REAVAESLYL DLEEVTPAED
310 320 330 340 350
GIYACLAENA YGQDNRTVEL SVMYAPWKPT VNGTVVAVEG ETVSILCSTQ
360 370 380 390 400
SNPDPILTIF KEKQILATVI YESQLQLELP AVTPEDDGEY WCVAENQYGQ
410 420 430 440 450
RATAFNLSVE FAPIILLESH CAAARDTVQC LCVVKSNPEP SVAFELPSRN
460 470 480 490 500
VTVNETEREF VYSERSGLLL TSILTLRGQA QAPPRVICTS RNLYGTQSLE
510 520 530 540 550
LPFQGAHRLM WAKIGPVGAV VAFAILIAIV CYITQTRRKK NVTESPSFSA
560 570 580 590 600
GDNPHVLYSP EFRISGAPDK YESEKRLGSE RRLLGLRGEP PELDLSYSHS
610 620
DLGKRPTKDS YTLTEELAEY AEIRVK
Length:626
Mass (Da):69,353
Last modified:April 1, 1988 - v1
Checksum:iE97998E280ECD635
GO
Isoform S-MAG (identifier: P07722-2) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     574-582: EKRLGSERR → REVSTRDCH
     583-626: Missing.

Show »
Length:582
Mass (Da):64,351
Checksum:i2A7A9A9FF76D48C4
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti309 – 310NA → KS (PubMed:6586369).Curated2
Sequence conflicti309 – 310NA → KS (PubMed:4020419).Curated2
Sequence conflicti309 – 310NA → KS (PubMed:6347394).Curated2

Alternative sequence

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Alternative sequenceiVSP_002529574 – 582EKRLGSERR → REVSTRDCH in isoform S-MAG. 1 Publication9
Alternative sequenceiVSP_002530583 – 626Missing in isoform S-MAG. 1 PublicationAdd BLAST44

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M14871 mRNA Translation: AAA41556.1
M22357 mRNA Translation: AAA41558.1
M16800 mRNA Translation: AAA41557.1
X05301 mRNA Translation: CAA28920.1
M11721 mRNA Translation: AAA42082.1
M36702 mRNA Translation: AAA40831.1
V01544 Genomic DNA Translation: CAA24786.1
PIRiA29028 BNRT3
RefSeqiNP_058886.1, NM_017190.4 [P07722-1]
XP_006228886.1, XM_006228824.3 [P07722-1]
XP_008757360.1, XM_008759138.2 [P07722-1]
XP_017444540.1, XM_017589051.1 [P07722-1]
XP_017444541.1, XM_017589052.1 [P07722-1]
XP_017444542.1, XM_017589053.1 [P07722-1]
UniGeneiRn.87331

Genome annotation databases

EnsembliENSRNOT00000028544; ENSRNOP00000028544; ENSRNOG00000021023 [P07722-1]
GeneIDi29409
KEGGirno:29409
UCSCiRGD:3035 rat [P07722-1]

Keywords - Coding sequence diversityi

Alternative splicing

Similar proteinsi

Entry informationi

Entry nameiMAG_RAT
AccessioniPrimary (citable) accession number: P07722
Secondary accession number(s): P02685, P07723
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 21, 1986
Last sequence update: April 1, 1988
Last modified: March 28, 2018
This is version 153 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

Complete proteome, Direct protein sequencing, Reference proteome