CD320
CD320 Molecule (TCblR) - Transcobalamin Receptor
Gene Information Card
| Symbol | CD320 |
|---|---|
| Full Name | CD320 Molecule |
| Gene Type | Protein coding |
| Chromosomal Location | 19p13.2 |
| NCBI Gene ID | 51293 ncbi.nlm.nih.gov/gene/51293 |
| Ensembl ID | ENSG00000167775 |
| UniProt ID | Q9NPF0 |
| OMIM ID | 606475 |
| HGNC ID | 16692 |
| Aliases | TCblR, 8D6, 8D6A |
Description
CD320 encodes the transcobalamin receptor (TCblR), a cell surface receptor that mediates cellular uptake of cobalamin (vitamin B12) bound to transcobalamin. The receptor is expressed on various tissues, including placenta, kidney, and brain. Mutations in CD320 cause methylmalonic aciduria due to transcobalamin receptor defect (OMIM #613646), a disorder of cobalamin metabolism leading to elevated methylmalonic acid and homocysteine levels.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Methylmalonic aciduria due to transcobalamin receptor defect | Loss-of-function mutations impair cobalamin internalization, causing intracellular cobalamin deficiency and accumulation of methylmalonic acid | ClinVar, OMIM #613646 |
| Cobalamin deficiency | Reduced receptor expression or function limits vitamin B12 uptake, contributing to deficiency states | NCBI Gene, UniProt |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Placenta | 12.5 | High |
| Kidney | 8.2 | Medium |
| Brain | 6.1 | Medium |
| Liver | 4.3 | Low |
| Heart | 3.8 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 15.0 | High expression |
| HeLa | 9.5 | Moderate expression |
| HepG2 | 6.2 | Low expression |
| K562 | 4.1 | Very low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.262G>A (p.Glu88Lys) | Missense | Rare | Impaired receptor function; associated with methylmalonic aciduria |
| c.1A>G (p.Met1Val) | Start loss | Rare | Loss of protein expression; pathogenic |
| c.445C>T (p.Arg149*) | Nonsense | Rare | Premature truncation; loss of function |
Mutation functional classification
Loss of Function (LOF)
Missense, nonsense, and start-loss mutations reduce or abolish cobalamin uptake, leading to methylmalonic aciduria.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported.
View complete mutation data：
Gene Ontology (GO)
| • signaling receptor activity (GO:0038023) | • plasma membrane (GO:0005886) |
| • cytoplasmic vesicle (GO:0031410) | • cobalamin metabolic process (GO:0009235) |
| • cobalamin transport (GO:0015889) |
Pathways
• Vitamin B12 (cobalamin) metabolism
• Cobalamin transport and cellular uptake
Protein Summary
CD320 is a 282-amino acid type I transmembrane glycoprotein with an extracellular domain that binds transcobalamin-cobalamin complexes. Upon binding, the complex is internalized via clathrin-mediated endocytosis, releasing cobalamin into the cytoplasm for conversion to active cofactors (methylcobalamin and adenosylcobalamin). The receptor is essential for cellular vitamin B12 homeostasis.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CD320 Knockout HEK293 Cell Line | EDJ-KQ11021 | Human | 51293 | Details Get a Quote |
| CD320 Knockout A-549 Cell Line | EDJ-KQ38911 | Human | 51293 | Details Get a Quote |
| CD320 Knockout HCT 116 Cell Line | EDJ-KQ38912 | Human | 51293 | Details Get a Quote |
| CD320 Knockout HeLa Cell Line | EDJ-KQ38913 | Human | 51293 | Details Get a Quote |
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