Human Inactive Tyrosine-Protein Kinase 7 (PTK7) Protein

Background

Protein Tyrosine Kinase 7 (PTK7) is an inactive receptor tyrosine kinase that plays a critical role in cell signaling, development, and Wnt pathway regulation. Unlike other kinases, PTK7 lacks catalytic activity due to mutations in its kinase domain but functions as a co-receptor to regulate signaling pathways. Structurally, PTK7 has multiple extracellular immunoglobulin-like domains, a transmembrane region, and a pseudokinase domain. It is widely expressed during embryonic development and in adult tissues, particularly in processes involving cell polarity, migration, and morphogenesis. PTK7 is crucial for Wnt signaling, especially the non-canonical planar cell polarity (PCP) pathway, where it regulates tissue organization and cell orientation. It also modulates processes such as angiogenesis, neural development, and epithelial cell migration. PTK7 has been implicated in cancer progression, including colorectal cancer, gastric cancer, and leukemia, where it promotes metastasis, angiogenesis, and resistance to apoptosis. Altered PTK7 expression is associated with poor prognosis in cancer patients. Given its importance in development and disease, PTK7 is being explored as a therapeutic target in oncology and regenerative medicine.