Phosphatidylinositol 3-kinase (PI3K) is necessary for thyroid stimulating hormone (TSH)-induced cell cycle progression. To determine the molecular mechanism linking PI3K to TSH, we have identified a ...serine residue in p85alpha super(PI3K) phosphorylated by protein kinase A (PKA) in vitro and in vivo. Expression of an alanine mutant (p85A) abolished cyclic AMP/TSH- induced cell cycle progression and was lethal in thyroid cells (FRTL-5). The aspartic version of the p85alpha super(PI3K) (p85D) inhibited apoptosis following TSH withdrawal. The p85alpha super(PI3K) wild type not the p85A bound PKA regulatory subunit RIIbeta in cells stimulated with cAMP or TSH. The binding of the aspartic version of p85alpha super(PI3K) to RIIbeta was independent of cAMP or TSH stimulation. Similarly, binding of PI3K to p21Ras and activation of AKT, a downstream PI3K target, were severely impaired in cells expressing the p85A mutant. Finally, we found that the catalytic activity of PI3K was stimulated by TSH in cells expressing the wild-type p85alpha super(PI3K) but not in cells expressing p85A. This latter mutant did not affect the epidermal growth factor-stimulated PI3K activity. We suggest that (1) TSH-cAMP-induced PKA phosphorylates p85alpha super(PI3K) at serine 83, (2) phosphorylated p85alpha super(PI3K) binds RIIbeta-PKA and targets PKAII to the membrane, and (3) PI3K activity and p21Ras binding to PI3K increase and activate PI3K downstream targets. This pathway is essential for the transmission of TSH-cAMP growth signals.
Changes in chlorophylls, chlorophyll degradation products and lutein in pistachio kernels (Pistacia vera L.) during roasting Pumilia, Gloria; Morgan J. CichonauthorDepartment of Food Science & Technology, The Ohio State University, 2015 Fyffe Ct., 110 Parker Food Science & Technology Building, Columbus, OH 43210, USA; Jessica L. CooperstoneauthorDepartment of Food Science & Technology, The Ohio State University, 2015 Fyffe Ct., 110 Parker Food Science & Technology Building, Columbus, OH 43210, USA ...
2015
Journal Article
We present and apply to VY Ari, IM Peg and HK Lac a new method to determine spot temperatures (Tsp) and areas (Arel) from the analysis of simultaneous light curves and temperature modulations deduced ...from line-depth ratios. A spot model, developed by us, has been applied to light and temperature curves. Grids of solutions with comparable χ-square have been found for a wide range of spot temperatures. The behavior of the solution grids for temperature and light curves in the Tsp–Arel plane is very different and a rather small and unique intersection area can be found. In our spot-model we used spectral energy distributions (SEDs) based on the Planck law and on model atmospheres to evaluate the flux ratio between spots and unspotted photosphere and we found higher spot temperatures with SEDs based on model atmospheres than on the Planck law.
"In previous papers in the linear and anisotropic case, constitutive relations, rate equations, temperature and energy equations were derived by the authors to describe the mechanical, thermal and ...transport properties of fluid-saturated crystals with porous channels defects, using a model developed by one of us (L. R.) in the framework of nonequilibrium thermodynamics. A structural permeability tensor `a la Kubik, rij , its gradient and its flux Vijk were introduced as internal variables in the thermodynamic state vector. Here, we work out in the isotropic and perfect isotropic linear cases the constitutive functions for the stress tensor, the entropy density, the chemical potentials, and also the rate equations for rij , Vijk, the fluid-concentration and the heat fluxes, describing disturbances propagating with finite velocity and presenting a relaxation time. The porous defects modify the thermal conductivity and when they have a density higher than a suitable characteristic value the thermal conductivity decreases. Furthermore, the closure of the system of equations, describing the media under consideration and linearized around a thermodynamic equilibrium state is obtained. The derived results may have great relevance in biology, medical sciences and in several technological sectors, like seismic engineering and nanotechnology (where high-frequency waves propagation is present and the properties variation rate of the considered medium is faster than the relaxation times of the fluxes towards their equilibrium value)."
PDF
