Detection, evaluation, and treatment of high blood cholesterol in adults (Adult Treatment Panel III)

Adiponectin (Ad) is a hormone secreted by adipocytes that regulates energy homeostasis and glucose and lipid metabolism. However, the signaling pathways that mediate the metabolic effects of Ad remain poorly identified. Here we show that phosphorylation and activation of the 5'-AMP-activated protein kinase (AMPK) are stimulated with globular and full-length Ad in skeletal muscle and only with full-length Ad in the liver. In parallel with its activation of AMPK, Ad stimulates phosphorylation of acetyl coenzyme A carboxylase (ACC), fatty-acid oxidation, glucose uptake and lactate production in myocytes, phosphorylation of ACC and reduction of molecules involved in gluconeogenesis in the liver, and reduction of glucose levels in vivo. Blocking AMPK activation by dominant-negative mutant inhibits each of these effects, indicating that stimulation of glucose utilization and fatty-acid oxidation by Ad occurs through activation of AMPK. Our data may provide a novel paradigm that an adipocyte-derived antidiabetic hormone, Ad, activates AMPK, thereby directly regulating glucose metabolism and insulin sensitivity in vitro and in vivo.

Adiponectin stimulates glucose utilization and fatty-acid oxidation by activating AMP-activated protein kinase

Class Switch Recombination and Hypermutation Require Activation-Induced Cytidine Deaminase (AID), a Potential RNA Editing Enzyme

Nutritional deprivation suppresses immune function The cloning of the obese gene and identification of its protein product leptin has provided fundamental insight into the hypothalamic regulation of body weight Circulating levels of this adipocyte-derived hormone are proportional to fat mass but maybe lowered rapidly by fasting or increased by inflammatory mediators The impaired T-cell immunity of mice now known to be defective in leptin (ob/ob) or its receptor (db/db), has never been explained Impaired cell-mediated immunity and reduced levels of leptin are both features of low body weight in humans Indeed, malnutrition predisposes to death from infectious diseases We report here that leptin has a specific effect on T-lymphocyte responses, differentially regulating the proliferation of naive and memory T cells Leptin increased Th1 and suppressed Th2 cytokine production Administration of leptin to mice reversed the immunosuppressive effects of acute starvation Our findings suggest a new role for leptin in linking nutritional status to cognate cellular immune function, and provide a molecular mechanism to account for the immune dysfunction observed in starvation

Leptin modulates the T-cell immune response and reverses starvation-induced immunosuppression

The SNF1/AMP-activated protein kinase (AMPK) family maintains the balance between ATP production and consumption in all eukaryotic cells. The kinases are heterotrimers that comprise a catalytic subunit and regulatory subunits that sense cellular energy levels. When energy status is compromised, the system activates catabolic pathways and switches off protein, carbohydrate and lipid biosynthesis, as well as cell growth and proliferation. Surprisingly, recent results indicate that the AMPK system is also important in functions that go beyond the regulation of energy homeostasis, such as the maintenance of cell polarity in epithelial cells.

AMP-activated/SNF1 protein kinases: conserved guardians of cellular energy.

An anthropoid-specific locus of orphan C to U RNA-editing enzymes on chromosome 22.

The apolipoprotein B gene is constitutively expressed in HepG2 cells: regulation of secretion by oleic acid, albumin, and insulin, and measurement of the mRNA half-life.

Yeast SNF1 is functionally related to mammalian AMP-activated protein kinase and regulates acetyl-CoA carboxylase in vivo

The p27 catalytic subunit of the apolipoprotein B mRNA editing enzyme is a cytidine deaminase.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/S0014-5793%2896%2901209-4

The α1 and α2 isoforms of the AMP-activated protein kinase have similar activities in rat liver but exhibit differences in substrate specificity in vitro

James Scott

Papers

An anthropoid-specific locus of orphan C to U RNA-editing enzymes on chromosome 22.

The apolipoprotein B gene is constitutively expressed in HepG2 cells: regulation of secretion by oleic acid, albumin, and insulin, and measurement of the mRNA half-life.

Yeast SNF1 is functionally related to mammalian AMP-activated protein kinase and regulates acetyl-CoA carboxylase in vivo

The p27 catalytic subunit of the apolipoprotein B mRNA editing enzyme is a cytidine deaminase.

The α1 and α2 isoforms of the AMP-activated protein kinase have similar activities in rat liver but exhibit differences in substrate specificity in vitro