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The evolutionarily conserved target of rapamycin (TOR) kinase acts as a master regulator that coordinates cell proliferation and growth by integrating nutrient, energy, hormone and stress signals in all eukaryotes.sup.1,2. Research has focused mainly on TOR-regulated translation, but how TOR orchestrates the global transcriptional network remains unclear. Here we identify ethylene-insensitive protein 2 (EIN2), a central integrator.sup.3-5 that shuttles between the cytoplasm and the nucleus, as a direct substrate of TOR in Arabidopsis thaliana. Glucose-activated TOR kinase directly phosphorylates EIN2 to prevent its nuclear localization. Notably, the rapid global transcriptional reprogramming that is directed by glucose-TOR signalling is largely compromised in the ein2-5 mutant, and EIN2 negatively regulates the expression of a wide range of target genes of glucose-activated TOR that are involved in DNA replication, cell wall and lipid synthesis and various secondary metabolic pathways. Chemical, cellular and genetic analyses reveal that cell elongation and proliferation processes that are controlled by the glucose-TOR-EIN2 axis are decoupled from canonical ethylene-CTR1-EIN2 signalling, and mediated by different phosphorylation sites. Our findings reveal a molecular mechanism by which a central signalling hub is shared but differentially modulated by diverse signalling pathways using distinct phosphorylation codes that can be specified by upstream protein kinases. In Arabidopsis, phosphorylation of EIN2 by TOR kinase in the presence of glucose prevents the nuclear localization of EIN2, showing that the glucose-TOR-EIN2 axis regulates the transcriptome independently of ethylene signalling pathways., Author(s): Liwen Fu [sup.1] [sup.2] , Yanlin Liu [sup.2] , Guochen Qin [sup.1] , Ping Wu [sup.3] , Hailing Zi [sup.1] , Zhongtian Xu [sup.1] , Xiaodi Zhao [sup.2] , [...]

A principal question in MAP kinase (MAPK/MPK) cascade signalling is how similar components dictate different specificity in the information-processing machineries from yeast to humans and plants. In Arabidopsis, how MPK3/6 [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cell.2006.09.028 Byline: Young-Hee Cho (1), Sang-Dong Yoo (1), Jen Sheen (1) Abstract: Arabidopsis hexokinase1 (HXK1) is a glucose sensor that integrates nutrient and hormone signals to govern gene expression and plant growth in response to environmental cues. How the metabolic enzyme mediates glucose signaling remains a mystery. By coupling proteomic and binary-interaction screens, we discover two nuclear-specific HXK1 unconventional partners: the vacuolar H.sup.+-ATPase B1 (VHA-B1) and the 19S regulatory particle of proteasome subunit (RPT5B). Remarkably, vha-B1 and rpt5b mutants uniquely share a broad spectrum of glucose response defects with the HXK1 mutant gin2 (glucose-insensitive2). Genetic and chromatin immunoprecipitation analyses suggest that the nuclear HXK1 forms a glucose signaling complex core with VHA-B1 and RPT5B that directly modulates specific target gene transcription independent of glucose metabolism. The findings support a model in which conserved metabolic enzymes and proteins of well-established activities may perform previously unrecognized nuclear functions. Author Affiliation: (1) Department of Molecular Biology, Massachusetts General Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02114, USA Article History: Received 1 May 2006; Revised 18 July 2006; Accepted 1 September 2006 Article Note: (miscellaneous) Published: November 2, 2006

Author(s): Shuichi Yanagisawa (corresponding author) [1, 2]; Sang-Dong Yoo [2]; Jen Sheen [2] Glucose is a global regulator of growth and metabolism that is evolutionarily conserved from unicellular microorganisms to [...]

Research was conducted to study the minority carrier transport characteristics of vacancy-doped p-type HgCdTe such as carrier concentration, lifetime, and mobility. Two independent singly ionized levels and a divalent level with two ionization energies were utilized to describe acceptor levels while carrier concentration values were computed from the charge neutrality condition. Results showed differences in the electron mobility of p type and n type semiconductors.

The n+-base width of a two-terminal vertical thyristor fabricated with n++(top-emitter)-p+(base)-n+(base)-p++(bottom-emitter) epitaxial Si layers was designed to produce a cross-point memory cell without a selector. Both the latch-up and latch-down voltages increased linearly with the n+-base width, but the voltage increase slope of the latch-up was 2.6 times higher than that of the latch-down, and the memory window increased linearly with the n+-base width. There was an optimal n+-base width that satisfied cross-point memory cell operation; i.e. ∼180 nm, determined by confirming that the memory window principally determined the condition of operation as a cross-point memory cell (i.e. one half of the latch-up voltage being less than the latch-down voltage and a sufficient voltage difference existing between the latch-up and latch-down voltages). The vertical thyristor designed with the optimal n+-base width produced write/erase endurance cycles of ∼109 by sustaining a memory margin (Ion/Ioff) of 102, and the cross-point memory cell array size of 1024 K sustained a sensing margin of 99 %, which is comparable with that of current dynamic random-access memory (DRAM). In addition, in the cross-point memory cell array, a ˝ bias scheme (i.e. a memory array size of 1024 K for 0.02 W of power consumption) resulted in lower power consumption than a bias scheme (i.e. a memory array size of 256 K for 0.02 W of power consumption). [ABSTRACT FROM AUTHOR]

The electron mobility in the inversion layer of metal oxide semiconductor field-effect transistors was calculated by using a Monte Carlo method. We utilized an improved matrix element for accurately calculating the surface roughness scattering among the many factors determining the electron mobility. The improved matrix element employed different effective electric fields (Eeff) for each subband energy level. From the simulation results, we demonstrated that the relative proportion of surface roughness scattering was about three times greater than that of acoustic phonon scattering at an electric field of 1 MV/cm. In particular, the electron mobility curve calculated with the improved matrix element showed better consistency with universal experimental data as compared to a curve calculated with a conventional matrix element. [ABSTRACT FROM AUTHOR]

Demonstrates the calculation of the low field electron mobility in n-type mercury cadmium telluride (HgCdTe) by using the relaxation time approximation method. Scattering mechanisms; Band-structure effects; Incorporation of degeneracy without approximation; Drift mobility.