In Fischer 344 rats, induction of gastric mucosal proliferative activity, whether the result of aging or injury or occurring after administration of epidermal growth factor, gastrin, or bombesin, is associated with a rise in tyrosine kinase activity and tyrosine phosphorylation of several mucosal proteins, including a protein with a molecular mass of 53-55 kDa. We hypothesized that this phospho...

Driver tyrosine kinase mutations are rare in sarcomas, and patterns of tyrosine phosphorylation are poorly understood. To better understand the signaling pathways active in sarcoma, we examined global tyrosine phosphorylation in sarcoma cell lines and human tumor samples. Anti-phosphotyrosine antibodies were used to purify tyrosine phosphorylated peptides, which were then identified by liquid c...

PD 166285, a novel protein tyrosine kinase inhibitor of a new structural class, the 6-aryl-pyrido[2,3-d]pyrimidines, was synthesized as the most potent and soluble analog of a series of small molecules originally identified by screening a compound library with assays that measured protein tyrosine kinase activity. PD 166285 was found to inhibit Src nonreceptor tyrosine kinase, fibroblast growth...

It has previously been demonstrated that the insulin-mimetic agent trypsin stimulates autophosphorylation of purified insulin receptors and activates the insulin receptor tyrosine kinase in vitro. We now report the effects of trypsin on whole cell tyrosine kinase activation and insulin receptor autophosphorylation. Trypsin treatment of intact adipocytes produces a time-dependent stimulation of ...

The extracellular domain of several membrane-anchored proteins can be released as a soluble fragment by the action of a cell surface endoproteolytic system. This cleavage results in the generation of a soluble and a cell-bound fragment. In the case of proteins with signaling capability, such as tyrosine kinase receptors, the cleavage process may have an effect on the kinase activity of the cell...

The lack of a conserved tyrosine autophosphorylation site is a unique feature of the C-terminal Src-kinase, Csk, although this protein tyrosine kinase can be autophosphorylated on tyrosine residues in vitro and in bacteria. Here we show that human Csk is tyrosine phosphorylated in HeLa cells treated with sodium pervanadate. Phosphorylation in vivo occurs mainly at Tyr-184 and in vitro mainly at...

Gefitinib is a selective tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR) used for the treatment malignant neoplasms. The most frequent skin complication during gefitinib therapy an acneiform papulopustular eruption, usually distributed in seborrheic areas but occasionally widespread. We report patient with erosive pustular dermatosis scalp, neutrophil-mediated disease prese...

Plasma cell membrane glycoprotein-1 (PC-1) inhibits insulin receptor (IR) tyrosine kinase activity and subsequent cellular signaling. PC-1 content is elevated in fibroblasts, muscle, and adipose tissue from insulin-resistant subjects, and its elevation correlates with in vivo insulin resistance. In vitro, when PC-1 is transfected and overexpressed in cultured cells, it inhibits IR tyrosine kina...