Tyrosine-protein kinase-like 7 also known as colon carcinoma kinase 4 (CCK4) is a

receptor tyrosine kinase Receptor tyrosine kinases (RTKs) are the high- affinity cell surface receptors for many polypeptide growth factors, cytokines, and hormones. Of the 90 unique tyrosine kinase genes identified in the human genome, 58 encode receptor tyrosine kin ...

that in humans is encoded by the ''PTK7''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

Function

Receptor protein tyrosine kinases transduce extracellular signals across the cell membrane. A subgroup of these kinases lack detectable catalytic tyrosine kinase activity but retain roles in signal transduction. The protein encoded by this gene an intracellular domain with tyrosine kinase homology and may function as a cell adhesion molecule. This gene is thought to be expressed in colon carcinomas but not in normal colon, and therefore may be a marker for or may be involved in tumor progression. Four transcript variants encoding four different isoforms have been found for this gene. PTK7 serves as a context-dependent signalling switch for the

Wnt pathway The Wnt signaling pathways are a group of signal transduction pathways which begin with proteins that pass signals into a cell through cell surface receptors. The name Wnt is a portmanteau created from the names Wingless and Int-1. Wnt signaling p ...

s (particularly in planar cell polarity related functions such as

convergent extension Convergent extension (CE), sometimes called convergence and extension (C&E), is the process by which the tissue of an embryo is restructured to converge (narrow) along one axis and extend (elongate) along a perpendicular axis by cellular movement. ...

and neural crest cell migration) and appears to have similar functions for

plexin A plexin is a protein which acts as a receptor for semaphorin family signaling proteins. It is classically known for its expression on the surface of axon growth cones and involvement in signal transduction to steer axon growth away from the so ...

and

Flt-1 Vascular endothelial growth factor receptor 1 is a protein that in humans is encoded by the ''FLT1'' gene. Function ''FLT1'' is a member of VEGF receptor gene family. It encodes a receptor tyrosine kinase which is activated by VEGF-A, VEGF-B, ...

pathways. PTK7 was identified to be highly expressed in colon cancer by Saha et al. using serial analysis of gene expression ( LongSAGE).Saha, S., et al. (2002). "Using the transcriptome to annotate the genome." Nat Biotechnol 20(5): 508-512.

Pfizer Pfizer Inc. ( ) is an American multinational pharmaceutical and biotechnology corporation headquartered on 42nd Street in Manhattan, New York City. The company was established in 1849 in New York by two German entrepreneurs, Charles Pfizer ...

is targeting PTK7 for cancer by generating an

antibody-drug conjugate Antibody-drug conjugates or ADCs are a class of biopharmaceutical drugs designed as a targeted therapy for treating cancer. Unlike chemotherapy, ADCs are intended to target and kill tumor cells while sparing healthy cells. As of 2019, some 56 phar ...

against the PTK7 receptor.

Function

References

Further reading