17 research outputs found
Reversible Control of Magnetic Interactions by Electric Field in a Single Phase Material
Intrinsic magnetoelectric coupling describes the interaction between magnetic
and electric polarization through an inherent microscopic mechanism in a single
phase material. This phenomenon has the potential to control the magnetic state
of a material with an electric field, an enticing prospect for device
engineering. We demonstrate 'giant' magnetoelectric cross-field control in a
single phase rare earth titanate film. In bulk form, EuTiO3 is
antiferromagnetic. However, both anti and ferromagnetic interactions coexist
between different nearest neighbor europium ions. In thin epitaxial films,
strain can be used to alter the relative strength of the magnetic exchange
constants. Here, we not only show that moderate biaxial compression
precipitates local magnetic competition, but also demonstrate that the
application of an electric field at this strain state, switches the magnetic
ground state. Using first principles density functional theory, we resolve the
underlying microscopic mechanism resulting in the EuTiO3 G-type magnetic
structure and illustrate how it is responsible for the 'giant' cross-field
magnetoelectric effect
Retrospective review of superficial femoral artery stenting in diabetic patients: thiazolidinedione use may decrease reinterventions
Mdm2 is involved in the ubiquitination and degradation of G-protein-coupled receptor kinase 2
G-protein-coupled receptor kinase 2 (GRK2) is a central regulator of G-protein-coupled receptor signaling. We report that Mdm2, an E3-ubiquitin ligase involved in the control of cell growth and apoptosis, plays a key role in GRK2 degradation. Mdm2 and GRK2 association is enhanced by β(2)-adrenergic receptor stimulation and β-arrestin. Increased Mdm2 expression accelerates GRK2 proteolysis and promotes kinase ubiquitination at defined residues, whereas GRK2 turnover is markedly impaired in Mdm2-deficient cells. Moreover, we find that activation of the PI3K/Akt pathway by insulin-like growth factor-1 alters Mdm2-mediated GRK2 degradation, leading to enhanced GRK2 stability and increased kinase levels. These data put forward a novel mechanism for controlling GRK2 expression in physiological and pathological conditions
TZDs inhibit vascular smooth muscle cell growth independently of the cyclin kinase inhibitors p21 and p27
Alteration of β-secretase traffic by the receptor tyrosine kinase signaling pathway – a new mechanism for regulating Alzheimer's β-amyloid production
β-Arrestin-1 links mitogenic sonic hedgehog signaling to the cell cycle exit machinery in neural precursors
Development of the cerebellum, a brain region regulating posture and coordination, occurs post-natally and is marked by rapid proliferation of granule neuron precursors (CGNPs), stimulated by mitogenic Sonic hedgehog (Shh) signaling. β-Arrestin (βArr) proteins play important roles downstream of Smoothened, the Shh signal transducer. However, whether Shh regulates βArrs and what role it plays in Shh-driven CGNP proliferation remains to be determined. Here, we report that Shh induces βArr1 accumulation and localization to the nucleus, where it participates in enhancing expression of the cyclin dependent kinase (cdk) inhibitor p27, whose accumulation eventually drives CGNP cell cycle exit. βArr1 knockdown enhances CGNP proliferation and reduces p27 expression. Thus, Shh-mediated βArr1 induction represents a novel negative feedback loop within the Shh mitogenic pathway, such that ongoing Shh signaling, while required for CGNPs to proliferate, also sets up a cell-intrinsic clock programming their ultimate exit from the cell cycle