Protein tyrosine kinase 7 (PTK7) (PTK7)

Protein tyrosine kinase 7 (PTK7), also known as colon carcinoma kinase 4 (CCK4), is a member of the receptor tyrosine kinase (RTK) family that lacks detectable catalytic activity, thus functioning as a pseudokinase (UniProt: P35091). It serves as a crucial co-receptor in the non-canonical Wnt signaling pathway, regulating processes such as planar cell polarity, cell migration, and embryonic development (PubMed: 25103565). PTK7 is frequently overexpressed in a variety of cancers, including leukemias and solid tumors like colorectal and lung cancer, where it is associated with poor prognosis and chemoresistance (PubMed: 28213370). Due to its high expression on the surface of cancer cells and its ability to undergo receptor-mediated endocytosis, PTK7 is a prominent target for antibody-drug conjugates (ADCs) like cofetuzumab pelidotin and aptamer-functionalized nanocarriers (PubMed: 16936728). Specifically, the sgc8c aptamer has been widely utilized to functionalize gold nanoparticles (AuNPs) for the targeted delivery of therapeutic agents to PTK7-positive cells, such as CCRF-CEM leukemia cells (PubMed: 22403971). Therapeutic strategies often focus on using PTK7 as a docking site for the delivery of cytotoxic agents or diagnostic probes.

Other names

CCK4Colon carcinoma kinase 4Tyrosine-protein kinase-like 7

Targeted delivery and internalization via receptor-mediated endocytosis; modulation of Wnt signaling pathways.