Showing papers on "Lipid kinase activity published in 2011"

PI3Kγ within a nonhematopoietic cell type negatively regulates diet-induced thermogenesis and promotes obesity and insulin resistance

Abstract: Obesity is associated with a chronic low-grade inflammation, and specific antiinflammatory interventions may be beneficial for the treatment of type 2 diabetes and other obesity-related diseases. The lipid kinase PI3Kγ is a central proinflammatory signal transducer that plays a major role in leukocyte chemotaxis, mast cell degranulation, and endothelial cell activation. It was also reported that PI3Kγ activity within hematopoietic cells plays an important role in obesity-induced inflammation and insulin resistance. Here, we show that protection from insulin resistance, metabolic inflammation, and fatty liver in mice lacking functional PI3Kγ is largely consequent to their leaner phenotype. We also show that this phenotype is largely based on decreased fat gain, despite normal caloric intake, consequent to increased energy expenditure. Furthermore, our data show that PI3Kγ action on diet-induced obesity depends on PI3Kγ activity within a nonhematopoietic compartment, where it promotes energetic efficiency for fat mass gain. We also show that metabolic modulation by PI3Kγ depends on its lipid kinase activity and might involve kinase-independent signaling. Thus, PI3Kγ is an unexpected but promising drug target for the treatment of obesity and its complications.

Regulation of autophagic activity by 14-3-3ζ proteins associated with class III phosphatidylinositol-3-kinase

Abstract: 14-3-3s are binding proteins with survival functions in cells by interaction with proteins involved in the regulation of cell fate. The role of 14-3-3 during autophagy was investigated, thus, a forced expression of 14-3-3ζ reduces C2-ceramide-induced autophagy, whereas depletion of 14-3-3ζ promotes autophagy. The 14-3-3 role in autophagyc-related proteins was also investigated. The human vacuolar protein sorting 34 (hVps34), the class III phosphatidylinositol-3-kinase mediates multiple vesicle-trafficking processes such as endocytosis and autophagy, its activation being a requirement for autophagy initiation. Using chromatography techniques, hVps34 were eluted from a 14-3-3 affinity column, showing also a direct interaction with 14-3-3 proteins under physiological condition. Further analysis suggests that hVps34/14-3-3 association is a phorbol-12-myristate-13-acetate-dependent phosphorylated mechanism promoting a strong inhibition of the hVps34 lipid kinase activity, proteins kinase C being the likely kinase involved in phosphorylation and 14-3-3 binding of hVps34 under physiological conditions. Meanwhile, stimulation of autophagy leads to the dissociation of the 14-3-3/hVps34 complex enhancing hVps34 lipid kinase activity. Forced expression of 14-3-3ζ reduces hVps34 kinase activity and depletion of 14-3-3ζ promotes upregulation of this activity. In this study, 14-3-3ζ proteins are shown as a negative regulator of autophagy through regulation of a key component of early stages of the autophagy pathway, such as hVps34.

Calpain interacts with class IA phosphoinositide 3-kinases regulating their stability and signaling activity

Abstract: Class IA phosphoinositide 3-kinases (PI3Ks) are signaling enzymes with key roles in the regulation of essential cellular functions and disease, including cancer. Accordingly, their activity is tightly controlled in cells to maintain homeostasis. The formation of multiprotein complexes is a ubiquitous mechanism to regulate enzyme activity but the contribution of protein–protein interactions to the regulation of PI3K signaling is not fully understood. We designed an affinity purification quantitative mass spectrometry strategy to identify proteins interacting dynamically with PI3K in response to pathway activation, with the view that such binding partners may have a functional role in pathway regulation. Our study reveals that calpain small subunit 1 interacts with PI3K and that the association between these proteins is lower in cells stimulated with serum compared to starved cells. Calpain and PI3K activity assays confirmed these results, thus demonstrating that active calpain heterodimers associate dynamically with PI3K. In addition, calpains were found to cleave PI3K proteins in vitro (resulting in a reduction of PI3K lipid kinase activity) and to regulate endogenous PI3K protein levels in vivo. Further investigations revealed that calpains have a role in the negative regulation of PI3K/Akt pathway activity (as measured by Akt and ribosomal S6 phosphorylation) and that their inhibition promotes cell survival during serum starvation. These results indicate that the interaction between calpain and PI3K is a novel mechanism for the regulation of class IA PI3K stability and activity.

Phosphoinositide-3-kinase inhibitors and pharmaceutical compositions containing said inhibitors

Abstract: FIELD: chemistry. ^ SUBSTANCE: invention relates to compounds of formulae and including their stereoisomers, as well as pharmaceutically acceptable salt, where X denotes O or S; R1 is selected from H, F, CI, Br, I, CN, -CR14R15-NR16R17, -CR14R15-NHR10, -(CR14R15)NR10R11, -(CR14R15)nNR12C(=Y)R10, -(CR14R15)nNR12S(O)2R10, -(CR14R15)mOR10, -(CR14R15)nS(O)2R10, -C(OR10)R11R14, -C(R14)=CR18R19, -C(=Y)OR10, -C(=Y)NR10R11, -C(=Y)NR12OR10, -C(=O)NR12S(O)2R10, -C(=O)NR12(CR14R15)mNR10R11, -NHR12, -NR12C(=Y)R10, -S(O)2R10, -S(O)2NR10R11, C2-C12 alkyl, C2-C8 alkenyl, C2-C8 alkynyl, C3-C4 carbocyclyl, piperidinyl, thiopyranyl, phenyl or C5-C6 heteroaryl; R2 is selected from H, C2-C12 alkyl and thiazolyl; R3 denotes a condensed bicyclic heteroaryl selected from indazole, indole, benzoimidazole, pyrrolopyridine, imidazopyridine and quinoline; R10, R11 and R12 independently denote H, C2-C12 alkyl, C3 carbocyclyl, heterocyclyl selected from pyrrolidine, morpholine and piperazine, phenyl or heteroaryl selected from pyrazole, pyridine, benzothiophene; or R10 and R11 together with a nitrogen atom with which they are bonded possibly form a saturated C3-C6 heterocyclic ring, possibly containing one additional ring atom selected from N or O, where said heterocyclic ring is possibly substituted with one or more groups independently selected from oxo, (CH2)mOR10, NR10R11, SO2R10, C(=O)R10, NR12S(O)R11, C(=Y)NR10R11, C1-C12 alkyl and heterocyclyl selected from pyrrolidine; R14 and R15 are independently selected from H or C1-C12 alkyl; R16 and R17 independently denote H or phenyl; R18 and R19 together with a carbon atom with which they are bonded form a C3-C20 heterocyclic ring, where said alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, phenyl, heteroaryl, piperidinyl and condensed bicyclic heteroaryl possibly substituted with one or more groups independently selected from F, CI, Br, I, CF3, -C(=Y)R10, -C(=Y)OR10, oxo, R10, -C(=Y)NR10R11, -(CR14R15)nNR10R11, -NR10R11, -NR12C(=Y)R10, -NR12C(=Y)NR10R11, -NR12SO2R10, OR10, SR10, -S(O)2R10, -S(O)2NR10R11, possibly substituted with carbocyclyl, selected from cyclopropyl, possibly substituted heterocyclyl selected from piperazine, possibly substituted with alkyl and alkylsulphonyl, pyrrolidine, morpholine, piperdine, possibly substituted CH3, phenyl and possibly substituted heteroaryl selected from imidazole and triazole; Y denotes O; m equals 0, 1 or 2; n equals 1 and t equals 2. The invention also relates to a pharmaceutical composition which modulates lipid kinase activity, based on said compounds. ^ EFFECT: obtaining novel compounds and a composition based on said compounds, which can be used to treat lipid kinase-mediated diseases, for example, cancer. ^ 48 cl, 2 tbl, 372 ex

The Nucleophosmin-Anaplastic Lymphoma Kinase Oncogene Interacts, Activates, and Uses the Kinase PIKfyve to Increase

Abstract: NPM-ALK is a chimeric tyrosine kinase detected in most anaplastic large cell lymphomas that results from the reciprocal translocation t(2,5)(p23;q35) that fuses the N-terminal domain of nucleophosmin (NPM) to the catalytic domain of the anaplastic lymphoma kinase (ALK) receptor. The constitutive activity of the kinase is responsible for its oncogenicity through the stimulation of several downstream signaling pathways, leading to cell proliferation, migration, and survival. We demonstrated previously that the high level of phosphatidylinositol 5-phosphate measured in NPM-ALK-expressing cells is controlled by the phosphoinositide kinase PIKfyve, a lipid kinase known for its role in vesicular trafficking. Here, we show that PIKfyve associates with NPM-ALK and that the interaction involves the 181– 300 region of the oncogene. Moreover, we demonstrate that the tyrosine kinase activity of the oncogene controls PIKfyve lipid kinase activity but is dispensable for the formation of the complex. Silencing or inhibition of PIKfyve using siRNA or the PIKfyve inhibitor YM201636 have no effect on NPM-ALK-mediated proliferation and migration but strongly reduce invasive capacities of NPM-ALK-expressing cells and their capacity to degrade the extracellular matrix. Accordingly, immunofluorescence studies confirm a perturbation of matrix metalloproteinase 9 localization at the cell surface and defect in maturation. Altogether, these results suggest a role for PIKfyve in NPMALK-mediated invasion.