TMEM126B
Transmembrane Protein 126B – Mitochondrial Complex I Assembly Factor
Gene Information Card
| Symbol | TMEM126B |
|---|---|
| Full Name | Transmembrane Protein 126B |
| Gene Type | Protein coding |
| Chromosomal Location | 11q14.1 |
| NCBI Gene ID | 55863 ncbi.nlm.nih.gov/gene/55863 |
| Ensembl ID | ENSG00000149476 |
| UniProt ID | Q8IUX1 |
| OMIM ID | 614177 |
| HGNC ID | 25425 |
| Aliases | HCCR-2, FLJ10769 |
Description
TMEM126B (Transmembrane Protein 126B) is a protein-coding gene located on chromosome 11q14.1. It encodes a mitochondrial inner membrane protein that functions as an assembly factor for mitochondrial complex I (NADH:ubiquinone oxidoreductase). TMEM126B is part of the mitochondrial complex I assembly complex (MCIA) and is required for the early stages of complex I biogenesis. Loss-of-function mutations in TMEM126B cause mitochondrial complex I deficiency, often presenting as Leigh syndrome or Leigh-like syndrome with neurological and metabolic manifestations.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Mitochondrial complex I deficiency, nuclear type 21 (MC1DN21) | Biallelic loss-of-function mutations in TMEM126B impair complex I assembly, leading to reduced OXPHOS capacity and ATP production. | OMIM #618251; multiple case reports with homozygosity for frameshift or nonsense variants. |
| Leigh syndrome | Defective complex I assembly due to TMEM126B mutations results in neurodegeneration and characteristic brainstem lesions. | ClinVar; literature reports of patients with Leigh syndrome phenotype and TMEM126B variants. |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Heart | 15.2 | Medium |
| Skeletal muscle | 12.8 | Medium |
| Liver | 8.5 | Low |
| Brain | 7.3 | Low |
| Kidney | 6.9 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 18.4 | High expression |
| HeLa | 14.1 | Medium expression |
| HepG2 | 11.3 | Medium expression |
| SH-SY5Y | 9.7 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Start loss | Rare | Loss of translation initiation; predicted loss of function |
| c.130C>T (p.Arg44*) | Nonsense | Rare | Premature stop; loss of function |
| c.287_288del (p.Leu96Profs*5) | Frameshift | Rare | Frameshift leading to truncated protein; loss of function |
| c.425G>A (p.Trp142*) | Nonsense | Rare | Premature stop; loss of function |
Mutation functional classification
Loss of Function (LOF)
All reported pathogenic TMEM126B mutations are loss-of-function (nonsense, frameshift, start loss) leading to complex I assembly defect.
Gain of Function (GOF)
No evidence of gain-of-function mutations in TMEM126B.
Dominant Negative (DN)
No evidence of dominant-negative effects; disease is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • mitochondrial inner membrane | • mitochondrial respiratory chain complex I assembly |
| • protein-containing complex binding | • mitochondrion |
Pathways
• Mitochondrial complex I assembly (MCIA complex)
• Oxidative phosphorylation
• Respiratory electron transport
Protein Summary
TMEM126B is a 229-amino acid mitochondrial inner membrane protein with two predicted transmembrane domains. It is a component of the mitochondrial complex I assembly (MCIA) complex, which includes NDUFAF1, ECSIT, and ACAD9. TMEM126B stabilizes the MCIA complex and facilitates the incorporation of early assembly modules into complex I. Defects in TMEM126B lead to impaired complex I assembly and mitochondrial dysfunction.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| TMEM126B Knockout HEK293 Cell Line | EDJ-KQ12231 | Human | 55863 | Details Get a Quote |
| TMEM126B Knockout A-549 Cell Line | EDJ-KQ40993 | Human | 55863 | Details Get a Quote |
| TMEM126B Knockout HCT 116 Cell Line | EDJ-KQ40994 | Human | 55863 | Details Get a Quote |
| TMEM126B Knockout HeLa Cell Line | EDJ-KQ39758 | Human | 55863 | Details Get a Quote |
Displaying Records 1 To 4 Of 4 Records
