PTK7
Description
The PTK7 (protein tyrosine kinase 7 (inactive)) is a protein-coding gene located on chromosome 6.
PTK7, also known as colon carcinoma kinase 4 (CCK4), is a receptor tyrosine kinase encoded by the PTK7 gene in humans. Unlike typical receptor tyrosine kinases, PTK7 lacks detectable catalytic tyrosine kinase activity but still plays a role in signal transduction. It possesses an intracellular domain with tyrosine kinase homology and may function as a cell adhesion molecule. PTK7 is primarily expressed in colon carcinomas, but not in normal colon tissue, suggesting a potential role in tumor progression. This gene has four transcript variants encoding four distinct isoforms. PTK7 acts as a context-dependent signaling switch for Wnt pathways, particularly in planar cell polarity functions like convergent extension and neural crest cell migration. It exhibits similar functions for plexin and Flt-1 pathways. PTK7 was identified as being highly expressed in colon cancer by Saha et al. using serial analysis of gene expression (LongSAGE). Pfizer is targeting PTK7 for cancer treatment by developing an antibody-drug conjugate against the PTK7 receptor.
PTK7, an inactive tyrosine kinase, plays a role in the Wnt signaling pathway, acting as a component of both the non-canonical (Wnt/planar cell polarity signaling) and canonical Wnt pathways. It is involved in various cellular processes, including cell adhesion, migration, polarity, proliferation, actin cytoskeleton reorganization, and apoptosis. PTK7 is crucial for embryogenesis, epithelial tissue organization, and angiogenesis.
PTK7 is also known as CCK-4, CCK4.
