Anaplastic lymphoma kinase (ALK) and Leukocyte receptor tyrosine kinase (LTK) (ALK / LTK)

Anaplastic lymphoma kinase (ALK) and Leukocyte receptor tyrosine kinase (LTK) are members of the insulin receptor superfamily of receptor tyrosine kinases. ALK is primarily expressed in the nervous system and regulates neuronal differentiation, while LTK is involved in B-cell development and ER-to-Golgi protein transport (UniProt P97793, P29376). These receptors are significant therapeutic targets because their kinase domains are frequently activated by gene fusions or point mutations in various cancers (PubMed: 34819664). Common malignancies associated with ALK include non-small cell lung cancer, anaplastic large cell lymphoma, and neuroblastoma. LTK fusions have also been identified as oncogenic drivers in a subset of lung adenocarcinomas. Because ALK and LTK share high sequence homology in their catalytic domains, many small-molecule inhibitors target both proteins. Therapeutic intervention involves tyrosine kinase inhibitors (TKIs) that compete with ATP for binding to the kinase domain. These drugs, such as crizotinib and lorlatinib, effectively block downstream signaling pathways like PI3K/AKT and MAPK/ERK. A major clinical challenge is the development of secondary resistance mutations that reduce drug binding affinity (PubMed: 28456787). Monitoring for these mutations and gene rearrangements is essential for patient selection and treatment optimization.

Other names

CD246TYK1Protein tyrosine kinase 1ALK tyrosine kinase receptorAnaplastic lymphoma receptor tyrosine kinase

Competitive inhibition of the ATP-binding site of the kinase domain, preventing downstream signaling through pathways such as PI3K/AKT, MAPK/ERK, and STAT3.