LMBRD1
LMBR1 Domain Containing 1
Gene Information Card
| Symbol | LMBRD1 |
|---|---|
| Full Name | LMBR1 Domain Containing 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 6q13 |
| NCBI Gene ID | 55788 ncbi.nlm.nih.gov/gene/55788 |
| Ensembl ID | ENSG00000111897 |
| UniProt ID | Q9NUN5 |
| OMIM ID | 612625 |
| HGNC ID | 23018 |
| Aliases | MAHCF, cblF, FLJ10173 |
Description
LMBRD1 encodes a lysosomal membrane protein that functions as a transporter for cobalamin (vitamin B12) from the lysosome to the cytoplasm. Mutations in this gene cause the cblF type of methylmalonic aciduria with homocystinuria, a disorder of cobalamin metabolism characterized by accumulation of cobalamin in lysosomes.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Methylmalonic aciduria with homocystinuria, cblF type | Loss-of-function mutations impair lysosomal cobalamin export, leading to combined deficiency of methylmalonyl-CoA mutase and methionine synthase. | OMIM #277380, ClinVar, multiple case reports |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.5 | Medium |
| Kidney | 10.3 | Medium |
| Placenta | 8.7 | Medium |
| Brain | 6.1 | Low |
| Heart | 5.4 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 14.2 | Hepatocellular carcinoma cell line |
| HEK 293 | 11.8 | Embryonic kidney cells |
| K-562 | 9.5 | Leukemia cell line |
| HeLa | 7.3 | Cervical adenocarcinoma cells |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1056delG (p.Leu353Serfs*3) | Frameshift | Rare | Loss of function; causes cblF disease |
| c.1A>G (p.Met1?) | Missense (start loss) | Rare | Loss of function; prevents translation initiation |
| c.1120C>T (p.Arg374*) | Nonsense | Rare | Premature stop; loss of function |
Mutation functional classification
Loss of Function (LOF)
Most reported LMBRD1 mutations are loss-of-function (frameshift, nonsense, start loss), leading to impaired lysosomal cobalamin export and combined methylmalonic aciduria/homocystinuria.
Gain of Function (GOF)
No gain-of-function mutations have been described for LMBRD1.
Dominant Negative (DN)
No dominant-negative mutations have been reported; the disorder is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • cobalamin transport (GO:0038028) | • lysosomal membrane (GO:0005765) |
| • transmembrane transporter activity (GO:0022857) | • cobalamin metabolic process (GO:0009235) |
Pathways
• Vitamin B12 metabolism (Reactome: R-HSA-196741)
• Cobalamin (B12) transport and metabolism (KEGG: hsa00860)
Protein Summary
LMBRD1 is a 540-amino acid lysosomal membrane protein with 6 predicted transmembrane domains. It mediates the export of cobalamin from lysosomes to the cytosol, where it is converted into active cofactors for methylmalonyl-CoA mutase and methionine synthase. Defects cause cblF disease.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| LMBRD1 Knockout HEK293 Cell Line | EDJ-KQ12130 | Human | 55788 | Details Get a Quote |
| LMBRD1 Knockout HeLa Cell Line | EDJ-KQ18213 | Human | 55788 | Details Get a Quote |
| LMBRD1 Knockout A-549 Cell Line | EDJ-KQ40821 | Human | 55788 | Details Get a Quote |
| LMBRD1 Knockout HCT 116 Cell Line | EDJ-KQ40822 | Human | 55788 | Details Get a Quote |
Displaying Records 1 To 4 Of 4 Records
