LTK (Leukocyte Receptor Tyrosine Kinase)
A receptor tyrosine kinase involved in nervous system development and cancer
Gene Information Card
| Symbol | LTK |
|---|---|
| Full Name | Leukocyte Receptor Tyrosine Kinase |
| Gene Type | Protein coding |
| Chromosomal Location | 15q15.1 |
| NCBI Gene ID | 4058 ncbi.nlm.nih.gov/gene/4058 |
| Ensembl ID | ENSG00000137868 |
| UniProt ID | P29376 |
| OMIM ID | 151520 |
| HGNC ID | 6721 |
| Aliases | TYK1, LTK1, ALK-like |
Description
The LTK gene encodes a receptor tyrosine kinase (RTK) of the insulin receptor superfamily. It is closely related to ALK (anaplastic lymphoma kinase). LTK is involved in neuronal development, axon guidance, and synaptic plasticity. Aberrant LTK signaling has been implicated in various cancers, including non-small cell lung cancer, breast cancer, and neuroblastoma. The protein is activated by binding of the ligand ALKAL2 (also known as FAM150B).
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Non-small cell lung cancer | LTK fusions (e.g., with CLIP1) lead to constitutive kinase activation and oncogenic signaling | COSMIC, ClinVar |
| Breast cancer | LTK overexpression and amplification associated with poor prognosis | COSMIC, NCBI |
| Neuroblastoma | LTK mutations and altered expression contribute to tumorigenesis | COSMIC, OMIM |
| Colorectal cancer | LTK upregulation linked to tumor progression | COSMIC |
| Gastric cancer | LTK amplification reported in a subset of cases | COSMIC |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.5 | Medium |
| Lung | 8.3 | Low |
| Breast | 6.1 | Low |
| Colon | 4.7 | Low |
| Stomach | 5.2 | Low |
| Ovary | 3.8 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| A549 (lung cancer) | 15.2 | High expression |
| MCF7 (breast cancer) | 9.8 | Moderate expression |
| SH-SY5Y (neuroblastoma) | 22.1 | Very high expression |
| HCT116 (colorectal cancer) | 7.4 | Low expression |
| HEK293 (embryonic kidney) | 4.3 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| p.Gly748Arg | Missense | 0.2% | Likely gain-of-function |
| p.Arg678Gln | Missense | 0.1% | Unknown significance |
| CLIP1-LTK fusion | Gene fusion | 0.5% | Oncogenic, constitutive activation |
| p.Leu799Phe | Missense | 0.05% | Likely benign |
Mutation functional classification
Loss of Function (LOF)
No well-characterized loss-of-function mutations reported in LTK.
Gain of Function (GOF)
CLIP1-LTK fusion and p.Gly748Arg are associated with constitutive kinase activation and oncogenic signaling.
Dominant Negative (DN)
No dominant-negative mutations described for LTK.
View complete mutation data：
Gene Ontology (GO)
| • transmembrane receptor protein tyrosine kinase activity (GO:0004714) | • transmembrane receptor protein tyrosine kinase signaling pathway (GO:0007169) |
| • integral component of membrane (GO:0016021) | • plasma membrane (GO:0005886) |
| • protein autophosphorylation (GO:0046777) | • axon guidance (GO:0007411) |
Pathways
• PI3K-Akt signaling pathway (KEGG: hsa04151)
• Ras signaling pathway (KEGG: hsa04014)
• MAPK signaling pathway (KEGG: hsa04010)
• Neurotrophin signaling pathway (KEGG: hsa04722)
Protein Summary
LTK is a single-pass type I transmembrane receptor tyrosine kinase. The extracellular domain contains a ligand-binding region, and the intracellular domain possesses a tyrosine kinase domain. Upon binding of ALKAL2, LTK dimerizes and autophosphorylates, activating downstream signaling cascades including PI3K/Akt, Ras/MAPK, and PLCγ. LTK is essential for normal development of the nervous system, particularly in axon guidance and synapse formation. In cancer, LTK fusions and mutations drive uncontrolled cell proliferation.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| LTK Knockout HEK293 Cell Line | EDJ-KQ5152 | Human | 4058 | Details Get a Quote |
| LTK Knockout HCT 116 Cell Line | EDJ-KQ28123 | Human | 4058 | Details Get a Quote |
| LTK Knockout HeLa Cell Line | EDJ-KQ53813 | Human | 4058 | Details Get a Quote |
| LTK Knockout A-549 Cell Line | EDJ-KQ62293 | Human | 4058 | Details Get a Quote |
| LTK Knockout HAP1 Cell Line | EDC08000 | Human | 4058 | Details Get a Quote |
