Class Of Receptor Tyrosine Kinases Research Articles

Muscle-specific trk-related receptor with a kringle domain defines a distinct class of receptor tyrosine kinases.

Little is known about the signaling pathways by which motoneurons induce synapses on muscle fibers, and no receptors for synapse-inducing signals have yet been identified. Because several other inductive events in development are mediated by receptor tyrosine kinases (RTKs), and because phosphotyrosine staining within muscle fibers is concentrated at synaptic sites, one possibility is that synapse-inducing signals are transduced by a RTK within the muscle fiber. We have used PCR to search for tyrosine kinases within the electric organ of the electric ray Torpedo californica, since this tissue is homologous to muscle but is much more densely innervated and is therefore a rich source of synaptic molecules. We have isolated a RTK that is specifically expressed in electric organ and skeletal muscle. The kinase domain of this receptor is related to the trk family of neurotrophin receptors, but unlike any previously described receptor, the extracellular region of this Torpedo RTK contains a kringle domain close to the transmembrane domain.

Protein Tyrosine Kinase Growth Factor Receptors and their Ligands in Development, Differentiation, and Cancer

Publisher Summary The protein tyrosine kinases (PTKs) are a thematic protein family––built around a highly conserved domain capable of phosphorylating protein substrates on tyrosine residues. Members of this family are made up as a mosaic of sensory, regulatory, and effector domains. Members of the receptor tyrosine kinases (RTK) family hold a number of structural features, such as an extracellular ligand-binding domain, a single transmembrane domain, a single protein tyrosine kinase domain, and one regulatory domain, which serves to reign in the catalytic activity of the PTK domain. This chapter discusses the structure of RTK, its developmental mutants, and tumorigenesis. The expression patterns of many human, murine, and Drosophila RTKs have been determined by Northern analysis of mRNAs from adult tissues. RTKs have been detected at elevated levels in particular types of tumor. RTKs may be overexpressed or inappropriately expressed in a ligand-independent activated form to transform cells. The chapter also reviews several aspects of the oncogenicity of members of the RTK family and the signal transduction pathways downstream of the activated receptor. The structural alterations associated with the acquisition of oncogenicity by members of RTK class of proteins are also focused in the chapter.