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Small heterodimer partner (SHP) is an atypical nuclear receptor expressed in heart that has been shown to inhibit the hypertrophic response. Here, we assessed the role of SHP in cardiac metabolism and inflammation. Mice fed a high-fat diet (HFD) displayed glucose intolerance accompanied by increased cardiac mRNA levels of Shp. In HL-1 cardiomyocytes, SHP overexpression inhibited both basal and insulin-stimulated glucose uptake and impaired the insulin signalling pathway (evidenced by reduced AKT and AS160 phosphorylation), similar to insulin resistant cells generated by high palmitate/high insulin treatment (HP/HI; 500μM/100nM). In addition, SHP overexpression increased Socs3 mRNA and reduced IRS-1 protein levels. SHP overexpression also induced Cd36 expression (~6.2 fold; p

11 páginas, 7 figuras., AMP-activated protein kinase (AMPK) is a metabolic stress-sensing kinase. We previously showed that glucose deprivation induces autophosphorylation of AMPKβ at threonine-148 (Thr-148), which prevents the binding of AMPK to glycogen. Furthermore, in MIN6 cells, AMPKβ1 binds to R6 (PPP1R3D), a glycogen-targeting subunit of protein phosphatase 1 (PP1), thereby regulating the glucose-induced inactivation of AMPK. Here, we further investigated the interaction of R6 with AMPKβ and the possible dependency on Thr-148 phosphorylation status. Yeast two-hybrid analyses and co-immunoprecipitation of the overexpressed proteins in HEK293T cells revealed that both AMPKβ1 and β2 wild-type (WT) isoforms bind to R6. The AMPKβ/R6 interaction was stronger with the muscle-specific β2-WT and required association with the substrate-binding motif of R6. When HEK293T cells or C2C12 myotubes were cultured in high-glucose medium, AMPKβ2-WT and R6 weakly interacted. In contrast, glycogen depletion significantly enhanced this protein interaction. Mutation of AMPKβ2 Thr-148 prevented the interaction with R6 irrespective of the intracellular glycogen content. Treatment with the AMPK activator oligomycin enhanced AMPKβ2/R6 interaction in conjunction with increased Thr-148 phosphorylation in cells grown in low glucose medium. These data are in accordance with R6 binding directly to AMPKβ2 when both proteins detach from the diminishing glycogen particle, which is simultaneous to increased AMPKβ2 Thr-148 autophosphorylation. Such model points to a possible control of AMPK by PP1-R6 upon glycogen depletion in muscle., DN is recipient of a VIDI-Innovational Research Grant from the Netherlands Organization of Scientific Research (NWO-ALW Grant no. 864.10.007). This work has further been supported by grants from the Spanish Ministry of Education and Science SAF2014-54604-C3-1-R and a grant from Generalitat Valenciana (PrometeoII/2014/029) to PS.

As a central regulator of metabolism, the AMP-activated protein kinase (AMPK) is an established therapeutic target for metabolic diseases. Beyond the metabolic area, the number of medical fields that involve AMPK grows continuously, expanding the potential applications for AMPK modulators. Even though indirect AMPK activators are used in the clinics for their beneficial metabolic outcome, the few described direct agonists all failed to reach the market to date, which leaves options open for novel targeting methods. As AMPK is not actually a single molecule and has different roles depending on its isoform composition, the opportunity for isoform-specific targeting has notably come forward, but the currently available modulators fall short of expectations. In this review, we argue that with the amount of available structural and ligand data, computer-based drug design offers a number of opportunities to undertake novel and isoform-specific targeting of AMPK.

The mammalian AMP-activated protein kinase (AMPK) is an obligatory αβγ heterotrimeric complex carrying a carbohydrate-binding module (CBM) in the β-subunit (AMPKβ) capable of attaching AMPK to glycogen. Nonetheless, AMPK localizes at many different cellular compartments, implying the existence of mechanisms that prevent AMPK from glycogen binding. Cell-free carbohydrate binding assays revealed that AMPK autophosphorylation abolished its carbohydrate-binding capacity. X-ray structural data of the CBM displays the central positioning of threonine 148 within the binding pocket. Substitution of Thr-148 for a phospho-mimicking aspartate (T148D) prevents AMPK from binding to carbohydrate. Overexpression of isolated CBM or β1-containing AMPK in cellular models revealed that wild type (WT) localizes to glycogen particles, whereas T148D shows a diffuse pattern. Pharmacological AMPK activation and glycogen degradation by glucose deprivation but not forskolin enhanced cellular Thr-148 phosphorylation. Cellular glycogen content was higher if pharmacological AMPK activation was combined with overexpression of T148D mutant relative to WT AMPK. In summary, these data show that glycogen-binding capacity of AMPKβ is regulated by Thr-148 autophosphorylation with likely implications in the regulation of glycogen turnover. The findings further raise the possibility of regulated carbohydrate-binding function in a wider variety of CBM-containing proteins., Journal of Biological Chemistry, 290 (18), ISSN:0021-9258, ISSN:1083-351X

Agricultural changes have caused severe decline in the common bird communities in Europe. Mitigating this loss requires both understanding of and way to predict how agriculture affects biodiversity. The objective of this paper is to test the different dynamic models coupling bird abundances with farming land use. The agro-ecological calibration relies on 2002-2009 data for 34 bird species and 14 agricultural systems in 620 small agricultural regions of metropolitan France. The models are compared based on indicators of goodness-of-fit and predictive quality. The results highlight the relevance of systemic, functional, and mechanistic relationships between the agriculture and bird populations in both descriptive and predictive contexts. However, it seems that the best dynamic models to describe the past trends are not necessarily the most relevant to predict the future trends although there is a similar subset of five models that emerges in both cases. Ranking these different models depends on both the objective (describing or predicting) and the chosen functional level for the analysis (total community, functional groups or species).

The energy-sensor AMP-activated protein kinase (AMPK) cycles between a glycogen-bound and a free state. The muscle-specific regulatory AMPKβ2 subunit carries a high affinity carbohydrate-binding module (CBM). Upon energy stress, such as exercise, AMPK localization at glycogen allows for rapid inhibition of glycogen synthesis, whereas cytosolic AMPK is capable of stimulating insulin-independent glucose uptake.

Disposal of glucose into muscular glycogen is diminished in type 2 diabetes (T2D). In response to various cellular stress signals, AMP-activated protein kinase (AMPK; αβγ) affects key metabolic pathways to equilibrate energy intake and expenditure. In muscle, activated AMPK increases insulin-independent glucose import, while inhibiting glycogen synthesis due to phosphorylation of glycogen synthase located at glycogen.

The nongenetic mechanisms required to sustain malignant tumor state are poorly understood. During the transition from benign tumors to malignant carcinoma, tumor cells need to repress differentiation and acquire invasive features. Using transcriptional profiling of cancer stem cells from benign tumors and malignant skin squamous cell carcinoma (SCC), we identified the nuclear receptor NR2F2 as uniquely expressed in malignant SCC. Using genetic gain of function and loss of function in vivo, we show that NR2F2 is essential for promoting the malignant tumor state by controlling tumor stemness and maintenance in mouse and human SCC. We demonstrate that NR2F2 promotes tumor cell proliferation, epithelial–mesenchymal transition and invasive features, while repressing tumor differentiation and immune cell infiltration by regulating a common transcriptional program in mouse and human SCCs. Altogether, we identify NR2F2 as a key regulator of malignant cancer stem cell functions that promotes tumor renewal and restricts differentiation to sustain a malignant tumor state. Blanpain and colleagues identify NR2F2 as a regulator of stemness and invasiveness that promotes tumor renewal and restricts differentiation to sustain squamous cell carcinomas.