CrkII belongs to a family of adaptor proteins that become tyrosine phosphorylated after various stimuli. We examined the role of CrkII tyrosine phosphorylation in fibronectin-induced cell migration. Overexpression of CrkII inhibited dephosphorylation of focal adhesion components such as p130 Crk-associated substrate (p130cas) and paxillin by protein tyrosine phosphatase 1B (PTP1B). Tyrosine-pho...

CrkII, a 40 kDa adaptor possessing a Src homology (SH)2 domain followed by two SH3 domains, although not endowed with catalytic activity, participates in intracellular signalling, presumably by activating the Ras pathway. CrkII was found to be phosphorylated in response to hepatocyte growth factor/scatter factor (HGF/SF) and to associate with the beta-subunit of the HGF receptor (MET). CrkII as...

Sphingosine 1-phosphate (S1P), a ligand for endothelial differentiation gene family proteins, is one of the most potent signal mediators released from activated platelets. Here, we report that S1P induces membrane ruffling of human umbilical vein endothelial cells (HUVECs) via the vascular endothelial growth factor receptor (VEGFR), Src family tyrosine kinase(s), and the CrkII adaptor protein. ...

Cyclophilin A (CypA) is overexpressed in a number of human cancer types, but the mechanisms by which the protein promotes oncogenic properties of cells are not understood. Here we demonstrate that CypA binds the CrkII adaptor protein and prevents it from switching to the inhibited state. CrkII influences cell motility and invasion by mediating signaling through its SH2 and SH3 domains. CrkII Ty...

Background and aims. Various morphologies are seen in different salivary gland tumorsor within an individual tumor, and the lesions show divers biological behaviors. Experimental results support the hypothesis that increased CrkII proto-oncogene is associated with cytokine-induced tumor initiation and progression by altering cell motility signaling pathway. The aim of this study was to assess t...

The Zap70 protein tyrosine kinase controls TCR-linked signal transduction pathways and is critical for T cell development and responsiveness. Following engagement of TCR, the Zap70 undergoes phosphorylation on multiple tyrosine residues that are implicated in the regulation of its catalytic activity and interaction with signaling effector molecules downstream of the TCR. We have shown previousl...

Crk adaptor proteins are key players in signal transduction from a variety of cell surface receptors. CrkI and CrkII, the two alternative spliced forms of CRK, possess an N-terminal Src homology 2 domain, followed by a Src homology 3 (SH3) domain, whereas CrkII possesses in addition a C-terminal linker region plus a SH3 domain, which operate as regulatory moieties. In this study, we investigate...

The human crk gene is translated into crkI and crkII by alternative splicing. crkII mRNA was detected both in normal brain and glioblastoma tissues, whereas crkI mRNA levels were quite low in normal brain and up-regulated in glioblastoma tissues. Expression of CrkI but not CrkII in glioblastoma U87MG cells induced transformation that stimulated cell migration and invasion concomitant with tyros...

Insulin stimulation of Chinese hamster ovary cells expressing the human insulin receptor resulted in a time-dependent decrease in the amount of GTP bound to Rap1. The inactivation of Rap1 was associated with an insulin-stimulated decrease in the amount of Rap1 that was bound to Raf1. In parallel with the dissociation of Raf1 from Rap1, there was an increased association of Raf1 with Ras. Concom...

background and aims. various morphologies are seen in different salivary gland tumorsor within an individual tumor, and the lesions show divers biological behaviors. experimental results support the hypothesis that increased crkii proto-oncogene is associated with cytokine-induced tumor initiation and progression by altering cell motility signaling pathway. the aim of this study was to assess t...