Tyrosine nonreceptor protein kinases

Protein tyrosine kinases Nonreceptor tyrosine kinases Cytoplasmic tyrosine kinases Tyrosylprotein kinase Hydroxyaryl-protein kinase... 

Mode of Activation of Nonreceptor Protein Tyrosine Kinases.256... 

In spite of having no intrinsic catalytic domains, activation of T lymphocytes commences with tyrosine phosphorylations, activation of PLC-v with production of IP3 and DAG, and elevation of cytosolic free Ca2+. Thus, the consequences of receptor ligation are not dissimilar from those induced by the receptors for EGF or PDGF. An early study trying to explain the induction of tyrosine kinase activity resulted in the discovery of the nonreceptor protein tyrosine kinase Lck (p56lck), a T-cell-specific member of the Src family. Lck is associated with the cytosolic tail of CD4 (in helper T cells) or CD8 (in cytotoxic T cells) (Figure 8.14). As mentioned, the extracellular domains of these... 

Nonreceptor protein tyrosine kinases contain a catalytic domain, as well as various regulatory domains important for proper functioning of the enzyme 416... 

Nonreceptor protein tyrosine kinases contain a catalytic domain, as well as various regulatory domains important for proper functioning of the enzyme. NRPTKs are found in the inner leaflet of the plasma membrane, cytosol, endosomal membranes and nucleus. These include the Src, Jak, Abl, Tec, Ack, Csk, Fak, Fes, Frk and Syk subfamilies (Fig. 24-3). Since a great deal is known about the structure and regulation of the Src family tyrosine kinase, we will use it to illustrate the principles in NRPTK signaling unique features in other subfamilies will be indicated... 

FIGURE 24-3 Nonreceptor protein tyrosine kinase (NRPTK) families. The family members are shown to the right and family name to the left of each NRPTK. Inset indicates the PTK catalytic domain and other domains for the regulation of localization and function. (From reference [5], with permission of Nature. Nature 2001.)... 

FIGURE 24-10 Schematic structures of nonreceptor protein tyrosine phosphatases (NRPTPs) and receptor protein tyrosine phosphatases (RPTPs). NRPTPs contain a catalytic domain and various regulatory domains. RPTPs are composed of an extracellular domain, a transmembrane domain and an intracellular domain with one or two catalytic domains. Like receptor protein tyrosine kinases, the structural features of the extracellular domains divide the RPTPs into different families. (With permission from reference [12]). 

NRPTK nonreceptor protein tyrosine kinase PMN progressive motor neuropathy... 

Taniguchi, T. Cytokine signaling through nonreceptor protein tyrosine kinases (1995) Science 268, 251-255... 

Elberg, G.,Z. He, J. Li, N. Sekar, andY. Shechter. 1997. Vanadate activates membranous nonreceptor protein tyrosine kinase in rat adipocytes. Diabetes 46 1684—1690. 

Fig. 11.1 Activation of MAPK pathway by Angll and ET-1 in VSMC. Stimulation of Angll and ET-1 receptors through Gq/n activation enhances the activity of PLCp. Activated PLC 3 converts PIP2 to IP3 and diacylglycerol (DAG). IP3 elevates the concentration of intracellular calcium and DAG activates PKC. PKC and/or Ca2+/calmodulin (CaM)-dependent protein kinases (CaMK) activate nonreceptor (NR) and/or receptor (R) protein tyrosine kinases. Activation of these components signals the stimulation of Ras/Raf/MEK/ERKl/2 and p70 s6k. ERK1/2 and p70 s6k are translocated to nucleus and regulate nuclear events by activating transcription factors through phosphorylation.

Protein tyrosine phosphatases play a crucial role in the control of the activity of receptor tyrosine kinases, nonreceptor tyrosine kinases, and the signaling pathways that they regulate. The importance of the tyrosine phosphatases for receptor tyrosine kinase signaling is illustrated by the observation that virtually all receptor tyrosine kinases can be activated, even in the absence of ligand, by treatment of cells with tyrosine phosphatase inhibitors, demonstrating that the activity of tyrosine kinases is continuously controlled by inhibitory tyrosine phosphatase action. As outlined above, the activity of most receptor tyrosine kinases is positively controlled by Tyr-phosphorylation in the activation loop. Protein tyrosine phosphatases that remove these stimulatory phosphate residues will inhibit receptor activity and the biological responses mediated by Tyr-phosphorylation-dependent signaling pathways. 

Sudol, M. Nonreceptor protein tyrosine kinases. Mol. Basis Hum. Cancer (Neel, B.G., Kumar, R., eds.) Futura, Mount Kisco, New York, 203-224 (1993)... 

Signaling pathways operated by nonreceptor proteins tyrosine kinase... 

Fyn is a nonreceptor tyrosine kinase related to Src that is frequently found in cell junctions. Die protein is N-myristoylated and palmitoylated and thereby becomes associated with caveolae-like membrane microdomains. Fyn can interact with a variety of other signaling molecules and control a diversity of biological processes such as T cell receptor signaling, regulation of brain function, and adhesion mediated signaling. 

S-acylated proteins include many GTP-binding regulatory proteins (G proteins), including most a subunits of heterotrimeric G-proteins and also many members of the Ras superfamily of monomeric G proteins, a number of G protein-coupled receptors, several nonreceptor tyrosine kinases, and a number of other signaling molecules, -acylation is posttranslational and reversible, a property that allows the cell to control... 

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