CAB39 (Calcium Binding Protein 39)
A scaffold protein in the LKB1-STRAD-MO25 complex regulating cell polarity and energy metabolism.
Gene Information Card
| Symbol | CAB39 |
|---|---|
| Full Name | Calcium Binding Protein 39 |
| Gene Type | Protein coding |
| Chromosomal Location | 2q37.1 |
| NCBI Gene ID | 51719 ncbi.nlm.nih.gov/gene/51719 |
| Ensembl ID | ENSG00000135924 |
| UniProt ID | Q9Y376 |
| OMIM ID | 612175 |
| HGNC ID | 20292 |
| Aliases | MO25, CGI-66, PRO1173 |
Description
CAB39 (Calcium Binding Protein 39), also known as MO25, is a scaffold protein that forms a heterotrimeric complex with STK11 (LKB1) and STRAD. This complex is essential for LKB1 kinase activity, which regulates cell polarity, energy metabolism, and tumor suppression. CAB39 is ubiquitously expressed and plays a role in AMPK-related kinase signaling.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Peutz-Jeghers Syndrome (related via LKB1 complex) | Indirect: CAB39 mutations may impair LKB1 complex function, though direct evidence is limited. | ClinVar, OMIM |
| Non-small cell lung cancer | CAB39 overexpression correlates with poor prognosis; may promote tumor growth via AMPK/mTOR pathway. | COSMIC, PubMed |
| Hepatocellular carcinoma | Upregulated in HCC; associated with metastasis and EMT. | COSMIC, PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 14.2 | Medium |
| Heart | 11.8 | Medium |
| Liver | 9.5 | Low |
| Kidney | 13.1 | Medium |
| Testis | 16.7 | High |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 12.5 | Cervical cancer cell line |
| A549 | 10.3 | Lung cancer cell line |
| HepG2 | 9.8 | Liver cancer cell line |
| HEK293 | 11.0 | Embryonic kidney cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | <0.01% | Likely loss of start codon; functional impact unknown |
| c.487C>T (p.Arg163Trp) | Missense | <0.01% | Reported in COSMIC; uncertain significance |
| c.739G>A (p.Glu247Lys) | Missense | <0.01% | Found in cancer samples; no functional data |
Mutation functional classification
Loss of Function (LOF)
Rare missense variants may disrupt protein-protein interactions with STRAD or LKB1, reducing complex stability.
Gain of Function (GOF)
Not described; no activating mutations reported.
Dominant Negative (DN)
Not described.
View complete mutation data：
Gene Ontology (GO)
Pathways
• LKB1 signaling pathway (Reactome: R-HSA-5628897)
• AMPK signaling (KEGG: hsa04152)
• mTOR signaling (KEGG: hsa04150)
Protein Summary
CAB39 (MO25) is a 40 kDa scaffold protein that binds STRAD and LKB1 to form an active kinase complex. It stabilizes the LKB1-STRAD interaction and is required for LKB1 catalytic activity. The protein contains a calmodulin-like domain but does not bind calcium. CAB39 is highly conserved and expressed in most tissues.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CAB39 Knockout HEK293 Cell Line | EDJ-KQ1180 | Human | 51719 | Details Get a Quote |
| CAB39L Knockout HEK293 Cell Line | EDJ-KQ1181 | Human | 81617 | Details Get a Quote |
| CAB39L Knockout HCT 116 Cell Line | EDJ-KQ19105 | Human | 81617 | Details Get a Quote |
| CAB39 Knockout A-549 Cell Line | EDJ-KQ20457 | Human | 51719 | Details Get a Quote |
| CAB39 Knockout HCT 116 Cell Line | EDJ-KQ20458 | Human | 51719 | Details Get a Quote |
| CAB39 Knockout HeLa Cell Line | EDJ-KQ20459 | Human | 51719 | Details Get a Quote |
| CAB39L Knockout A-549 Cell Line | EDJ-KQ20460 | Human | 81617 | Details Get a Quote |
| CAB39L Knockout HeLa Cell Line | EDJ-KQ20461 | Human | 81617 | Details Get a Quote |
