When Brassica nigra leaf petiole suspension cells were subjected to 7 days of inorganic phosphate (Pi) starvation the extractable activity of: (a) pyrophosphate:fructose 6-phosphate 1-phosphotransferase, nonphosphorylating NADP-glyceraldehyde 3-phosphate dehydrogenase, phosphoenolpyruvate phosphatase, and phosphoenolpyruvate carboxylase increased at least fivefold, (b) phosphorylating NAD-glyce...

Chemotactic cells translate shallow chemoattractant gradients into a highly polarized intracellular response that includes the localized production of PI(3,4,5)P(3) on the side of the cell facing the highest chemoattractant concentration. Research over the past decade began to uncover the molecular mechanisms involved in this localized signal amplification controlling the leading edge of chemot...

The initiation of apoptosis often transpires in the presence of agents that regulate cell survival. This study evaluated the effects of stress-induced ceramide on the anti-apoptotic activity of the phosphoinositide-3 kinase [PI(3)K] pathway. PI(3)K activity is directly down-regulated by stress-induced ceramide in a dose-dependent manner with rapid kinetics and high specificity. Ceramide inhibit...

PURPOSE To compare PDGF- and insulin/IGF-1-induced class I(A) PI 3-kinase/Akt survival signaling in normal retinas and retinal ganglion cells (RGCs). METHODS Normal rat retinas and RGC-5 cells were used for (1) immunohistochemical and immunoblot studies to detect PDGF receptor (PDGFR) subtypes and (2) immunoprecipitation, immunoblot, and in vitro lipid kinase assays to determine basal and PDG...

BACKGROUND In insulin-sensitive cells, such as adipocytes and skeletal muscle, the activation of phosphoinositide 3-kinase (PI 3-kinase) is thought to be critical in allowing insulin to stimulate both the uptake of glucose and the translocation of a specialized glucose transporter, GLUT4, to the plasma membrane. However, the downstream mediators that couple PI 3-kinase to GLUT4 translocation ar...

Ras and Rho family GTPases have been ascribed important roles in signalling pathways determining cellular morphology and growth. Here we investigated the roles of the GTPases Ras, Cdc42, Rac1, and Rho and that of phosphatidylinositol 3-kinase (PI 3-kinase) in the pathway leading from serum starvation to neurite outgrowth in N1E-115 neuroblastoma cells. Serum-starved cells grown on a laminin mat...

In the paper, we refine and extend Cusa-Huygens inequality by simple functions. particular, determine sharp bounds for $$\sin x /x$$ of form $$(2+\cos x)/3 -(2/3-2/\pi )\Upsilon (x)$$ , where $$\Upsilon (x)>0$$ $$x\in (0, \pi /2)$$ (0)=0$$ (\pi /2)=1$$ such that x/x$$ proposed coincide at $$x=0$$ $$x=\pi /2$$ . The hierarchy obtained is discussed, along with a graphical study. Also, alternative...