
**NCBI Gene Summary**: This gene encodes a protein that has been associated with several biological functions including cellular magnesium uptake, protein glycosylation and embryonic development. This protein localizes to the endoplasmic reticulum and acts as a component of the oligosaccharyl transferase complex which is responsible for N-linked protein glycosylation. This gene is a candidate tumor suppressor gene. Homozygous mutations in this gene are associated with autosomal recessive nonsyndromic mental retardation-7 and in the proliferation and invasiveness of several cancers including metastatic pancreatic cancer, ovarian cancer and glioblastoma multiform. [provided by RefSeq, Oct 2017]

**GeneCards Summary**: TUSC3 (Tumor Suppressor Candidate 3) is a Protein Coding gene. Diseases associated with TUSC3 include Intellectual Developmental Disorder, Autosomal Recessive 7 and Autosomal Recessive Non-Syndromic Intellectual Disability. Among its related pathways are Translation of Structural Proteins and Infectious disease. Gene Ontology (GO) annotations related to this gene include magnesium ion transmembrane transporter activity and dolichyl-diphosphooligosaccharide-protein glycotransferase activity. An important paralog of this gene is MAGT1.

**UniProtKB/Swiss-Prot Summary**: Acts as accessory component of the N-oligosaccharyl transferase (OST) complex which catalyzes the transfer of a high mannose oligosaccharide from a lipid-linked oligosaccharide donor to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains. Involved in N-glycosylation of STT3B-dependent substrates. Specifically required for the glycosylation of a subset of acceptor sites that are near cysteine residues; in this function seems to act redundantly with MAGT1. In its oxidized form proposed to form transient mixed disulfides with a glycoprotein substrate to facilitate access of STT3B to the unmodified acceptor site. Has also oxidoreductase-independent functions in the STT3B-containing OST complex possibly involving substrate recognition. Magnesium transporter.
