Catherine J. Pallen

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Akt/PKB is a serine/threonine kinase that promotes tumor cell growth by phosphorylating transcription factors and cell cycle proteins. There is particular interest in finding tumor-specific substrates for Akt to understand how this protein functions in cancer and to provide new avenues for therapeutic targeting. Our laboratory sought to identify novel Akt(More)
We demonstrate here that Chinese hamster ovary cells stably expressing PRL-3, a M(r) 20000 prenylated protein tyrosine phosphatase, or its relative, PRL-1, exhibit enhanced motility and invasive activity. A catalytically inactive PRL-3 mutant has significantly reduced migration-promoting activity. We observe that PRL-3 is associated with diverse membrane(More)
The kinase activity of pp60c-src is specifically and transiently increased during mitosis and repressed during interphase. Loss of cell-cycle control of pp60c-src occurs on mutation of Tyr527 to Phe or when pp60c-src is associated with polyoma middle-T-antigen, and these conditions result in cell transformation or tumorigenesis. In both cases, pp60c-src has(More)
Axon-derived molecules are temporally and spatially required as positive or negative signals to coordinate oligodendrocyte differentiation. Increasing evidence suggests that, in addition to the inhibitory Jagged1/Notch1 signaling cascade, other pathways act via Notch to mediate oligodendrocyte differentiation. The GPI-linked neural cell recognition molecule(More)
PRL-1, -2, and -3 represent a novel class of protein-tyrosine phosphatase with a C-terminal prenylation motif. Although PRL-1 has been suggested to be associated with the nucleus, the presence of three highly homologous members and the existence of a prenylation motif call for a more detailed examination of their subcellular localization. In the present(More)
We have examined the in vivo activity of receptor-like protein-tyrosine phosphatase alpha (PTPalpha) toward p59(fyn), a widely expressed Src family kinase. In a coexpression system, PTPalpha effected a dose-dependent tyrosine dephosphorylation and activation of p59(fyn), where maximal dephosphorylation correlated with a 5-fold increase in kinase activity.(More)
Signals from fibronectin-binding integrins promote neural crest cell motility during development in part through protein-tyrosine kinase (PTK) activation. Neuroblastoma (NB) is a neural crest malignancy with high metastatic potential. We find that alpha4 and alpha5 integrins are present in late-stage NB tumors and cell lines derived thereof. To determine(More)
A role for the receptor-like protein tyrosine phosphatase alpha (PTPalpha) in regulating the kinase activity of Src family members has been proposed because ectopic expression of PTPalpha enhances the dephosphorylation and activation of Src and Fyn [1] [2] [3]. We have generated mice lacking catalytically active PTPalpha to address the question of whether(More)
The Y-box binding protein 1 (YB-1) is upregulated in many human malignancies including glioblastoma (GBM). It is also essential for normal brain development, suggesting that YB-1 is part of a neural stem cell (NSC) network. Here, we show that YB-1 was highly expressed in the subventricular zone (SVZ) of mouse fetal brain tissues but not in terminally(More)
Calcineurin, a calmodulin-binding protein from brain, has been shown to possess a metal ion-dependent and calmodulin-stimulated phosphatase activity towards phosphorylase kinase and inhibitor-1 (Stewart, A. A., Ingebritsen, T. S., Manalan, A., Klee, C. B., and Cohen, P. (1982) FEBS Lett. 137, 80-84). In this report, we show that calcineurin can also(More)