FNTA (Farnesyltransferase, CAAX Box, Alpha)
Alpha subunit of protein farnesyltransferase, a key enzyme in post-translational prenylation of Ras and other CAAX-motif proteins.
Gene Information Card
| Symbol | FNTA |
|---|---|
| Full Name | Farnesyltransferase, CAAX Box, Alpha |
| Gene Type | Protein coding |
| Chromosomal Location | 8p11.21 |
| NCBI Gene ID | 2339 ncbi.nlm.nih.gov/gene/2339 |
| Ensembl ID | ENSG00000130513 |
| UniProt ID | P49354 |
| OMIM ID | 134635 |
| HGNC ID | 3778 |
| Aliases | FTA, FPTA, PTAR2 |
Description
The FNTA gene encodes the alpha subunit of protein farnesyltransferase (FTase), a heterodimeric enzyme that catalyzes the addition of a farnesyl group to the cysteine residue of proteins containing a C-terminal CAAX motif. This prenylation is essential for the membrane localization and function of many signaling proteins, including Ras family GTPases. The alpha subunit is common to both farnesyltransferase and geranylgeranyltransferase type I.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Hereditary gingival fibromatosis type 1 (HGF1) | Missense mutations in FNTA disrupt farnesyltransferase activity, leading to altered cell signaling and connective tissue overgrowth. | OMIM #135300; PMID: 21499247 |
| Cancer (Ras-driven) | FNTA overexpression or altered activity can enhance Ras farnesylation, promoting oncogenic signaling. | COSMIC; PMID: 25926053 |
| Progeroid syndromes (theoretical) | Defective prenylation due to FNTA mutations may contribute to nuclear lamina abnormalities. | Inferred from ZMPSTE24/FACE1 pathway; PMID: 16403807 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 12.3 | Medium |
| Adrenal gland | 10.1 | Medium |
| Thyroid | 9.8 | Medium |
| Brain (cerebellum) | 8.5 | Medium |
| Liver | 7.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 14.5 | High expression |
| HeLa | 11.2 | Medium expression |
| K562 | 9.0 | Medium expression |
| A549 | 8.1 | Medium expression |
| MCF7 | 6.3 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.109G>A (p.Gly37Arg) | Missense | <0.01% | Reduced farnesyltransferase activity; associated with HGF1 |
| c.287T>C (p.Leu96Pro) | Missense | <0.01% | Impaired enzyme stability; HGF1 |
| c.1A>G (p.Met1Val) | Start loss | <0.01% | Loss of protein expression; HGF1 |
| c.1048C>T (p.Arg350Trp) | Missense | <0.01% | Unknown functional effect; ClinVar |
Mutation functional classification
Loss of Function (LOF)
Missense mutations (e.g., p.Gly37Arg, p.Leu96Pro) reduce farnesyltransferase activity, leading to HGF1.
Gain of Function (GOF)
Not well documented; overexpression in some cancers may enhance Ras farnesylation.
Dominant Negative (DN)
Not reported for FNTA.
View complete mutation data：
Gene Ontology (GO)
| • GO:0004660 – protein farnesyltransferase activity | • GO:0005960 – farnesyltransferase complex |
| • GO:0018344 – protein farnesylation | • GO:0005737 – cytoplasm |
| • GO:0005829 – cytosol |
Pathways
• Protein prenylation (R-HSA-597592)
• Signaling by Ras (R-HSA-5673001)
• Metabolism of proteins (R-HSA-392499)
Protein Summary
The FNTA protein (alpha subunit of farnesyltransferase) is 379 amino acids long with a molecular weight of ~44 kDa. It forms a heterodimer with the beta subunit (FNTB) to create the active farnesyltransferase enzyme. The alpha subunit contains a leucine-rich repeat domain essential for substrate recognition. It is ubiquitously expressed, with highest levels in testis and adrenal gland.
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