Exposures to subtoxic concentrations of iAs or MAs inhibit GLUT4 association with the plasma membrane of insulin-activated adipocytes

<p><b>Copyright information:</b></p><p>Taken from "Molecular Mechanisms of the Diabetogenic Effects of Arsenic: Inhibition of Insulin Signaling by Arsenite and Methylarsonous Acid"</p><p></p><p>Environmental Health Perspectives 2007;115(5):734-742.</p><p>Published online 29 Jan 2007</p><p>PMCID:PMC1867998.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI</p> Immunofluorescent images of GLUT4 in plasma membrane lawns isolated from control (untreated) 3T3-L1 adipocytes before () and after activation () with insulin and from insulin-activated adipocytes treated for 4 hr with 50 μM iAs () or 2 μM MAs (). Adipocytes were fixed and sonicated to prepare plasma membrane lawns. GLUT4 was labeled with an anti-GLUT4 antibody and visualized with a fluorescent secondary antibody. Representative fields of two independent experiments are shown. Bars = 10 μm

Exposures to subtoxic concentrations of iAs or MAs do not affect insulin signal mediators that regulate PIP levels in insulin-activated adipocytes

<p><b>Copyright information:</b></p><p>Taken from "Molecular Mechanisms of the Diabetogenic Effects of Arsenic: Inhibition of Insulin Signaling by Arsenite and Methylarsonous Acid"</p><p></p><p>Environmental Health Perspectives 2007;115(5):734-742.</p><p>Published online 29 Jan 2007</p><p>PMCID:PMC1867998.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI</p> () Immunoblot analyses of the activated PI-3K, total PTEN, and phosphorylated PTEN (Ser380) in control 3T3-L1 adipocytes before or after activation with insulin and in insulin-activated adipocytes treated for 4 hr with 50 μM iAs or 2 μM MAs. Activated PI-3K was immunoprecipitated from control and exposed cells with an anti-phospho-Tyr (PY20) antibody and immunoblotted with an antibody against the regulatory (p85) subunit. Representative blots of three independent experiments are shown. () The ratio of phosphorylated PTEN (Ser380) to total PTEN expressed as a percent of the ratio found in control adipocytes before activation with insulin. Each value represents the mean ± SD; = 3 experiments

Molecular Mechanisms of the Diabetogenic Effects of Arsenic: Inhibition of Insulin Signaling by Arsenite and Methylarsonous Acid-1

<p><b>Copyright information:</b></p><p>Taken from "Molecular Mechanisms of the Diabetogenic Effects of Arsenic: Inhibition of Insulin Signaling by Arsenite and Methylarsonous Acid"</p><p></p><p>Environmental Health Perspectives 2007;115(5):734-742.</p><p>Published online 29 Jan 2007</p><p>PMCID:PMC1867998.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI</p

Molecular Mechanisms of the Diabetogenic Effects of Arsenic: Inhibition of Insulin Signaling by Arsenite and Methylarsonous Acid-8

<p><b>Copyright information:</b></p><p>Taken from "Molecular Mechanisms of the Diabetogenic Effects of Arsenic: Inhibition of Insulin Signaling by Arsenite and Methylarsonous Acid"</p><p></p><p>Environmental Health Perspectives 2007;115(5):734-742.</p><p>Published online 29 Jan 2007</p><p>PMCID:PMC1867998.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI</p

Molecular Mechanisms of the Diabetogenic Effects of Arsenic: Inhibition of Insulin Signaling by Arsenite and Methylarsonous Acid-6

<p><b>Copyright information:</b></p><p>Taken from "Molecular Mechanisms of the Diabetogenic Effects of Arsenic: Inhibition of Insulin Signaling by Arsenite and Methylarsonous Acid"</p><p></p><p>Environmental Health Perspectives 2007;115(5):734-742.</p><p>Published online 29 Jan 2007</p><p>PMCID:PMC1867998.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI</p

Molecular Mechanisms of the Diabetogenic Effects of Arsenic: Inhibition of Insulin Signaling by Arsenite and Methylarsonous Acid-0

<p><b>Copyright information:</b></p><p>Taken from "Molecular Mechanisms of the Diabetogenic Effects of Arsenic: Inhibition of Insulin Signaling by Arsenite and Methylarsonous Acid"</p><p></p><p>Environmental Health Perspectives 2007;115(5):734-742.</p><p>Published online 29 Jan 2007</p><p>PMCID:PMC1867998.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI</p

Four-hour exposures to subtoxic concentrations of iAs or MAs do not increase DNA fragmentation in cultured adipocytes

<p><b>Copyright information:</b></p><p>Taken from "Molecular Mechanisms of the Diabetogenic Effects of Arsenic: Inhibition of Insulin Signaling by Arsenite and Methylarsonous Acid"</p><p></p><p>Environmental Health Perspectives 2007;115(5):734-742.</p><p>Published online 29 Jan 2007</p><p>PMCID:PMC1867998.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI</p> DNA fragmentation was measured by TUNEL in 3T3-L1 adipocytes treated with 50 μM iAs or 2 μM MAs for 4, 24, 48, and 72 hr. Untreated adipocytes were used as controls. Color images show green fluorescein signal of fragmented DNA in apoptotic cells. Gray-scale images illustrate the corresponding cell morphology. Representative fields of two independent experiments are shown. Bars = 40 μm

Identification of two novel mutations in <i>RASGRP2</i> affecting platelet CalDAG-GEFI expression and function in patients with bleeding diathesis

<p>The <i>RASGRP2</i> gene encodes the Ca²⁺ and DAG-regulated guanine nucleotide exchange factor I (CalDAG-GEFI), which plays a key role in integrin activation in platelets and neutrophils. We here report two new <i>RASGRP2</i> variants associated with platelet dysfunction and bleeding in patients. The homozygous patients had normal platelet and neutrophil counts and morphology. Platelet phenotyping showed: prolonged PFA-100 closure times; normal expression of major glycoprotein receptors; severely reduced platelet aggregation response to ADP and collagen (both patients); aggregation response to PAR1 and arachidonic acid markedly impaired in one patient; PMA-induced aggregation unaffected; platelet secretion, clot retraction, and spreading minimally affected. Genetic analysis identified two new homozygous variants in <i>RASGRP2</i>: c.706C>T (p.Q236X) and c.887G>A (p.C296Y). In both patients, CalDAG-GEFI protein was not detectable in platelet lysates, and platelet αIIbβ3 activation, as assessed by fibrinogen binding, was greatly impaired in response to all agonists except PMA. Patient neutrophils showed normal integrin expression, but impaired Mn^2<b>+</b>-induced fibrinogen binding. In summary, we have identified two new <i>RASGRP2</i> mutations that can be added to this rapidly growing form of inherited platelet function disorder.</p