Inhibition of p130cas tyrosine phosphorylation by calyculin A

Inhibition of Bcr serine kinase by tyrosine phosphorylation.

The first exon of the BCR gene encodes a new serine/threonine protein kinase. Abnormal fusion of the BCR and ABL genes, resulting from the formation of the Philadelphia chromosome (Ph), is the hallmark of Ph-positive leukemia. We have previously demonstrated that the Bcr protein is tyrosine phosphorylated within first-exon sequences by the Bcr-Abl oncoprotein. Here we report that in addition to...

Tyrosine phosphorylation of paxillin, FAK, and p130CAS: effects on cell spreading and migration.

Integrins are transmembrane receptors that mediate cell attachment to the substrate. At the cytoplasmic surface of the integrin, cytoskeletal proteins cluster into focal adhesions. The focal adhesions contain multiple proteins that provide a structural and signaling complex inside the cell. This review focuses on three of the cytoskeletal components of the focal adhesion, paxillin, FAK, and p13...

Protein Tyrosine Phosphatases Isolated T Cell Membrane by Inhibition of Regulation of Tyrosine Phosphorylation in

Tyrosine phosphorylation and association of p130Cas and c-Crk II by ANG II in vascular smooth muscle cells.

In cultured vascular smooth muscle cells (VSMC), angiotensin II (ANG II) stimulated tyrosine phosphorylation of multiple proteins including a 130-kDa protein. This 130-kDa protein was identified as a Crk-associated substrate, p130Cas. ANG II-stimulated tyrosine phosphorylation of p130Cas was rapid, concentration dependent, and inhibited by the AT1-receptor antagonist CV-11974. Neither downregul...

NHE3 function and phosphorylation are regulated by a calyculin A-sensitive phosphatase.

Na+/H+ exchanger 3 (NHE3) is phosphorylated and regulated by multiple kinases, including PKA, SGK1, and CK2; however, the role of phosphatases in the dephosphorylation and regulation of NHE3 remains unknown. The purpose of this study was to determine whether serine/threonine phosphatases alter NHE3 activity and phosphorylation and, if so, at which sites. To this end, we first examined the effec...