Alt. symbols: DKFZp564K142 | IAP | OST3B | MRX95 | SLC58A1

Approved name: magnesium transporter 1
Alt. names: oligosaccharyltransferase 3 homolog B (S. cerevisiae)

Location: Xq21.1: 77825747 - 77899271 (-)
Gene type: protein_coding, 13 transcripts.

Scores: LoFtool: 0.338000 | pLI: 0.88737388 | LOEUF: 0.326

HGNC: 28880

NCBI: 84061, RefSeq: NG_016390.1

Ensembl: ENSG00000102158.22

LRG_353 | Status: public

OMIM: 300715

Expression | ProteinAtlas

Gene Ontology (GO)

• Molecular function:
• Cell component: oligosaccharyltransferase complex [GO:0008250]
• Biological process: protein N-linked glycosylation via asparagine [GO:0018279]

Normal function

MAGT1 encodes a highly selective Mg(2+) transporter and acts as an accessory protein for STT3B, 1 of the catalytic subunits of the oligosaccharyltransferase (OST) complex, which transfers nascent glycan chains onto ER proteins during N-glycosylation.

Dysfunction and disease

X-linked mutations in MAGT1 are associated with Congenital disorder of glycosylation (CDG), type Icc [OMIM: 301031}, as well as with a syndromic X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection and neoplasia (XMEN) [OMIM:300853] which can share biochemical features of the former. XMEN is characterized by CD4 lymphopenia, severe chronic viral infections (especially EBV), and defective T-cell activation (PMID: 21796205). This is thought to be due to an abrogated T-cell specific transient Mg(2+) influx upon antigen receptor engagement, leading to impaired signal transduction such as defective phospholipase Cγ1 activation and Ca(2+) influx. Some patients may have elevated B cell counts, as well as variable or intermittent deficiencies in Ig levels and vaccine responses. Thus, in those with milder T-cell phenotypes, XMEN may potentially be diagnosed as CVID and MAGT1 mutations were indeed identified in a cohort of CVID patients by WES (PMID: 31942606). Additionally, Au et al. (2022) recently reported the identification of a novel MAGT1 mutation (c.916del) in a patient diagnosed with CVID on the basis of recurrent infections, hypogammaglobulinemia, and ITP (PMID: 35198253). He showed reduced switched memory B cells and plasmablasts despite an elevated total B cell count, as well as decreased expression of NKG2D in his NK cells and CD8+ T cells upon further investigation. [Load More]