The term kinase describes a broad class of enzymes responsible for catalyzing the transfer of a phosphoryl group from a nucleoside triphosphate donor (eg, ATP) to a receptor molecule. Tyrosine kinases catalyze the phosphorylation of tyrosine residues in proteins. Phosphorylation of tyrosine residues in turn leads to changes in the function of the proteins they contain. Phosphorylation of tyrosine residues controls the broad properties of proteins such as enzymatic activity, subcellular localization and intermolecular interactions. Furthermore, tyrosine kinases play a role in many signal transduction cascades, where extracellular signals are transmitted through the cell membrane to the cytoplasm and often to the nucleus where gene expression can be modified. Finally, mutations can turn some tyrosine kinases into constitutive activities, an uninterrupted state of function that may contribute to the development or progression of cancer.
Tyrosine kinases play a role in a variety of processes, pathways, and behaviors and are responsible for key events in the body. Receptor tyrosine kinases play a role in transmembrane signaling, while intracellular tyrosine kinases act in signal transduction into the nucleus. Tyrosine kinase activity in the nucleus involves cell cycle control and transcription factor characteristics. In fact, tyrosine kinase activity is involved in the induction of mitosis or mitosis in cells in this way; proteins in the cytoplasm and proteins in the nucleus are phosphorylated at the tyrosine residue during this process. Cell growth and reproduction may depend to some extent on tyrosine kinases. Tyrosine kinase function has been observed in the nuclear matrix, which does not include chromatin, but rather a nuclear envelope and a "web" for physically stabilizing DNA. Specifically, Lyn is a kinase in the Src family identified in the nuclear matrix and appears to control the cell cycle. The Src family of tyrosine kinases is closely related but has multiple functions. The role or expression of the Src family tyrosine kinase varies significantly depending on the cell type and during cell growth and differentiation. The Lyn and Src family tyrosine kinases are known to generally play a role in signal transduction pathways. There is evidence that Lyn is located on the cell membrane; Lyn is physically and functionally associated with a variety of receptor molecules.
Fibroblasts - a kind of cell that synthesizes extracellular matrix and collagen and is involved in wound healing - have been transformed with polyomaviruses and have higher tyrosine activity in the cell matrix. In addition, tyrosine kinase activity has been determined to be associated with cell transformation. Phosphorylation of the T antigen on tyrosine has also been shown to be associated with cell transformation, which is similar to cell growth or reproduction。 Another possible role of protein tyrosine kinases is that the effects of the inhibitors tyrphostin and genistein are related to protein tyrosine kinases in the context of endotoxin-induced circulatory failure and organ dysfunction in rats.
1. Schaller MD, et al.; pp125FAK a structurally distinctive protein-tyrosine kinase associated with focal adhesions .Proceedings of the National Academy of Sciences of the United States of America.1992,89 (11): 5192-6.
2. Ruetten H, et al.; Effects of tyrphostins and genistein on the circulatory failure and organ dysfunction caused by endotoxin in the rat: a possible role for protein tyrosine kinase. British Journal of Pharmacology. 1997,122 (1): 59-70.