Biomaterial Database

The protein tyrosine kinase inhibitor herbimycin A, but not genistein, specifically inhibits signal transduction by the T cell antigen receptor. 1992

M Graber, and C H June, and L E Samelson, and A Weiss

Department of Medicine, University of California, San Francisco 94143.

Several lines of evidence implicate a regulatory tyrosine phosphorylation in the activation of phospholipase C (PLC) by the T cell antigen receptor (TCR). These include studies using inhibitors of protein tyrosine kinases (PTKs). In Jurkat T cells expressing the heterologous human muscarinic receptor (HM1), PLC activity can be induced by either the TCR or HM1. HM1 activates PLC via a guanine nucleotide binding protein. We have studied the selectivity of the effects of the PTK inhibitors, herbimycin A and genistein, in this system. The results indicate that these inhibitors have different mechanisms of action, and suggest that herbimycin A, but not genistein, is a specific inhibitor of PTKs in T cells. Herbimycin A markedly inhibited both the resting and induced levels of phosphotyrosine-containing proteins, including the gamma 1 isozyme of PLC and the zeta chain of the TCR, and prevented activation of PLC by anti-TCR mAb. Herbimycin A did not inhibit activation of PLC by HM1. Genistein had a much less pronounced effect than herbimycin A on the appearance of tyrosine phosphoproteins. Moreover, genistein inhibited activation of PLC by both the TCR and HM1, and inhibition was only partial. Genistein was cytotoxic and markedly inhibited protein synthesis in both Jurkat cells and human peripheral lymphocytes. Herbimycin A was not cytotoxic. These findings confirm the role of a regulatory tyrosine phosphorylation in activation of PLC by the TCR. Herbimycin A was a selective inhibitor of a subclass of PTKs in Jurkat cells. In contrast, inhibition of signal transduction and later events in T cells by genistein may be due to effects other than direct inhibition of PTK activity.

UI	MeSH Term	Description	Entries
D007529	Isoflavones	3-Phenylchromones. Isomeric form of FLAVONOIDS in which the benzene group is attached to the 3 position of the benzopyran ring instead of the 2 position.	3-Benzylchroman-4-One,3-Benzylidene-4-Chromanone,Homoisoflavone,Homoisoflavones,Isoflavone,Isoflavone Derivative,3-Benzylchroman-4-Ones,3-Benzylidene-4-Chromanones,Isoflavone Derivatives,3 Benzylchroman 4 One,3 Benzylchroman 4 Ones,3 Benzylidene 4 Chromanone,3 Benzylidene 4 Chromanones,Derivative, Isoflavone,Derivatives, Isoflavone
D008214	Lymphocytes	White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.	Lymphoid Cells,Cell, Lymphoid,Cells, Lymphoid,Lymphocyte,Lymphoid Cell
D010738	Type C Phospholipases	A subclass of phospholipases that hydrolyze the phosphoester bond found in the third position of GLYCEROPHOSPHOLIPIDS. Although the singular term phospholipase C specifically refers to an enzyme that catalyzes the hydrolysis of PHOSPHATIDYLCHOLINE (EC 3.1.4.3), it is commonly used in the literature to refer to broad variety of enzymes that specifically catalyze the hydrolysis of PHOSPHATIDYLINOSITOLS.	Lecithinase C,Phospholipase C,Phospholipases, Type C,Phospholipases C
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D011499	Protein Processing, Post-Translational	Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.	Amino Acid Modification, Post-Translational,Post-Translational Modification,Post-Translational Protein Modification,Posttranslational Modification,Protein Modification, Post-Translational,Amino Acid Modification, Posttranslational,Post-Translational Amino Acid Modification,Post-Translational Modifications,Post-Translational Protein Processing,Posttranslational Amino Acid Modification,Posttranslational Modifications,Posttranslational Protein Processing,Protein Processing, Post Translational,Protein Processing, Posttranslational,Amino Acid Modification, Post Translational,Modification, Post-Translational,Modification, Post-Translational Protein,Modification, Posttranslational,Modifications, Post-Translational,Modifications, Post-Translational Protein,Modifications, Posttranslational,Post Translational Amino Acid Modification,Post Translational Modification,Post Translational Modifications,Post Translational Protein Modification,Post Translational Protein Processing,Post-Translational Protein Modifications,Processing, Post-Translational Protein,Processing, Posttranslational Protein,Protein Modification, Post Translational,Protein Modifications, Post-Translational
D011500	Protein Synthesis Inhibitors	Compounds which inhibit the synthesis of proteins. They are usually ANTI-BACTERIAL AGENTS or toxins. Mechanism of the action of inhibition includes the interruption of peptide-chain elongation, the blocking the A site of ribosomes, the misreading of the genetic code or the prevention of the attachment of oligosaccharide side chains to glycoproteins.	Protein Synthesis Antagonist,Protein Synthesis Antagonists,Protein Synthesis Inhibitor,Antagonist, Protein Synthesis,Antagonists, Protein Synthesis,Inhibitor, Protein Synthesis,Inhibitors, Protein Synthesis,Synthesis Antagonist, Protein,Synthesis Inhibitor, Protein
D011505	Protein-Tyrosine Kinases	Protein kinases that catalyze the PHOSPHORYLATION of TYROSINE residues in proteins with ATP or other nucleotides as phosphate donors.	Tyrosine Protein Kinase,Tyrosine-Specific Protein Kinase,Protein-Tyrosine Kinase,Tyrosine Kinase,Tyrosine Protein Kinases,Tyrosine-Specific Protein Kinases,Tyrosylprotein Kinase,Kinase, Protein-Tyrosine,Kinase, Tyrosine,Kinase, Tyrosine Protein,Kinase, Tyrosine-Specific Protein,Kinase, Tyrosylprotein,Kinases, Protein-Tyrosine,Kinases, Tyrosine Protein,Kinases, Tyrosine-Specific Protein,Protein Kinase, Tyrosine-Specific,Protein Kinases, Tyrosine,Protein Kinases, Tyrosine-Specific,Protein Tyrosine Kinase,Protein Tyrosine Kinases,Tyrosine Specific Protein Kinase,Tyrosine Specific Protein Kinases
D011809	Quinones	Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
D011948	Receptors, Antigen, T-Cell	Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens (CD3 COMPLEX). Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta (RECEPTORS, ANTIGEN, T-CELL, ALPHA-BETA) or gamma-delta (RECEPTORS, ANTIGEN, T-CELL, GAMMA-DELTA) chains.	Antigen Receptors, T-Cell,T-Cell Receptors,Receptors, T-Cell Antigen,T-Cell Antigen Receptor,T-Cell Receptor,Antigen Receptor, T-Cell,Antigen Receptors, T Cell,Receptor, T-Cell,Receptor, T-Cell Antigen,Receptors, T Cell Antigen,Receptors, T-Cell,T Cell Antigen Receptor,T Cell Receptor,T Cell Receptors,T-Cell Antigen Receptors
D011976	Receptors, Muscarinic	One of the two major classes of cholinergic receptors. Muscarinic receptors were originally defined by their preference for MUSCARINE over NICOTINE. There are several subtypes (usually M1, M2, M3....) that are characterized by their cellular actions, pharmacology, and molecular biology.	Muscarinic Acetylcholine Receptors,Muscarinic Receptors,Muscarinic Acetylcholine Receptor,Muscarinic Receptor,Acetylcholine Receptor, Muscarinic,Acetylcholine Receptors, Muscarinic,Receptor, Muscarinic,Receptor, Muscarinic Acetylcholine,Receptors, Muscarinic Acetylcholine