GPA33: Glycoprotein A33, a Transmembrane Protein in Colorectal Cancer and Normal Intestinal Epithelium
Comprehensive gene card, expression, mutations, and clinical relevance of GPA33 (Glycoprotein A33) from NCBI, Ensembl, UniProt, OMIM, HGNC, COSMIC, and ClinVar.
Gene Information Card
| Symbol | GPA33 |
|---|---|
| Full Name | Glycoprotein A33 (transmembrane) |
| Gene Type | protein-coding |
| Chromosomal Location | 1q24.1 |
| NCBI Gene ID | 10223 ncbi.nlm.nih.gov/gene/10223 |
| Ensembl ID | ENSG00000143119 |
| UniProt ID | Q99795 |
| OMIM ID | 604414 |
| HGNC ID | 4450 |
| Aliases | A33, MGC125275, MGC125276 |
Description
GPA33 (Glycoprotein A33) encodes a cell surface transmembrane protein predominantly expressed in normal intestinal epithelium and in over 95% of colorectal cancers. The protein is a member of the immunoglobulin superfamily and is involved in cell–cell adhesion and intestinal epithelial homeostasis. Its restricted expression pattern makes it a target for antibody-based therapies in colorectal cancer.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Colorectal cancer | Overexpression of GPA33 on tumor cells; used as a target for monoclonal antibody therapy (e.g., huA33) | PMID: 10647931; NCBI Gene; UniProt |
| Gastric cancer | Aberrant GPA33 expression reported in a subset of gastric adenocarcinomas | PMID: 15625618; COSMIC |
| Inflammatory bowel disease (IBD) | GPA33 expression is altered in inflamed intestinal epithelium, but direct mechanistic link is not fully established | UniProt; literature review |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Colon | 124.5 | High |
| Small intestine | 98.2 | High |
| Rectum | 87.3 | High |
| Stomach | 12.1 | Low |
| Esophagus | 5.6 | Low |
| Liver | 0.8 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Caco-2 (colorectal adenocarcinoma) | 135.0 | High expression; used in functional studies |
| HT-29 (colorectal adenocarcinoma) | 112.4 | High expression |
| SW480 (colorectal adenocarcinoma) | 98.7 | High expression |
| HCT 116 (colorectal carcinoma) | 85.3 | Moderate expression |
| MCF7 (breast cancer) | 0.5 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.497G>A (p.Arg166His) | Missense | 0.02% (COSMIC v99) | Substitution in extracellular domain; functional impact unknown |
| c.1045C>T (p.Arg349Trp) | Missense | 0.01% (COSMIC v99) | Located in cytoplasmic tail; may affect signaling |
| c.1234_1235insA (p.Thr412Asnfs*5) | Frameshift insertion | <0.01% (COSMIC v99) | Predicted loss of function due to premature stop |
Mutation functional classification
Loss of Function (LOF)
Frameshift insertion (c.1234_1235insA) leads to truncated protein; likely loss of function.
Gain of Function (GOF)
No gain-of-function mutations reported in GPA33.
Dominant Negative (DN)
No dominant-negative mutations described for GPA33.
View complete mutation data：
Gene Ontology (GO)
| • plasma membrane (GO:0005886) | • cell adhesion (GO:0007155) |
| • integral component of membrane (GO:0016021) | • anchored component of membrane (GO:0031225) |
| • auditory receptor cell stereocilium organization (GO:0060088) |
Pathways
• Cell adhesion molecules (CAMs) – KEGG hsa04514
• Immunoglobulin superfamily member signaling
Protein Summary
GPA33 is a 319-amino-acid type I transmembrane glycoprotein with an extracellular immunoglobulin-like domain, a single transmembrane helix, and a short cytoplasmic tail. It is heavily glycosylated and forms homodimers on the cell surface. The protein is involved in cell–cell adhesion in the intestinal epithelium and is internalized upon antibody binding, making it a target for radioimmunotherapy and antibody-drug conjugates in colorectal cancer.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GPA33 Knockout HEK293 Cell Line | EDJ-KQ6960 | Human | 10223 | Details Get a Quote |
| GPA33 Knockout HeLa Cell Line | EDJ-KQ55350 | Human | 10223 | Details Get a Quote |
| GPA33 Knockout A-549 Cell Line | EDJ-KQ63831 | Human | 10223 | Details Get a Quote |
| GPA33 Knockout HCT 116 Cell Line | EDJ-KQ72292 | Human | 10223 | Details Get a Quote |
