Synthesis and biological activity of phosphatidylinositol-3,4,5-trisphosphorothioate.
Ontology highlight
ABSTRACT:
SUBMITTER: Zhang H
PROVIDER: S-EPMC2255567 | biostudies-literature | 2008 Jan
REPOSITORIES: biostudies-literature
Publications
Synthesis and biological activity of phosphatidylinositol-3,4,5-trisphosphorothioate.
Zhang Honglu H Xu Yong Y Markadieu Nicolas N Beauwens Renaud R Erneux Christophe C Prestwich Glenn D GD
Bioorganic & medicinal chemistry letters 20071117 2
Metabolically-stabilized analogs of PtdIns(3,4,5)P(3) have shown long-lived agonist activity for cellular events mediated by this phosphoinositide. We describe an efficient method for the total asymmetric synthesis of the trisphosphorothioate (PT) analog of PtdIns(3,4,5)P(3). Intracellular delivery of dipalmitoyl PtdIns(3,4,5)PT(3)-mimicked insulin in activating sodium transport in A6 cells. ...[more]
Similar Datasets
Project description:The activation of phosphatidylinositol 3-kinase (PI 3-K) and subsequent production of PtdIns(3,4,5)P3 launches a signal transduction cascade that impinges on a plethora of downstream effects on cell physiology. Control of PI 3-K and PtdIns(3,4,5)P3 levels is an important therapeutic target in treatments for allergy, inflammation, cardiovascular, and malignant human diseases. We designed metabolically stabilized, that is, phosphatase resistant, analogues of PtdIns(3,4,5)P3 as probes for long-lived potential agonists or potential antagonists for cellular events mediated by PtdIns(3,4,5)P3. In particular, two types of analogues were prepared containing phosphomimetics that would be selectively resistant to the lipid 3-phosphatase PTEN. The total asymmetric synthesis of the 3-phosphorothioate-PtdIns(3,4,5)P3 and 3-methylenephosphonate-PtdIns(3,4,5)P3 analogues is described. These two analogues showed differential binding to PtdIns(3,4,5)P3 binding modules, and both were potential long-lived activators that mimicked insulin action in sodium transport in A6 cells.
| S-EPMC2535794 | biostudies-literature
Project description:The membrane phospholipid phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) is an important regulator in cell physiology. Hydrolysis of PtdIns(4,5)P2 by phospholipase C (PLC) releases two second messengers, Ins(1,4,5)P3 and diacylglycerol. To dissect the effects of PtdIns(4,5)P2 from those resulting from PLC-generated signals, a metabolically stabilized analogue of PtdIns(4,5)P2 was required. Two analogues were designed in which the scissile O-P bond was replaced with a C-P bond that could not be hydrolyzed by PLC activity. Herein we describe the asymmetric total synthesis of the first metabolically stabilized phospholipase C-resistant analogues of PtdIns(4,5)P2. The key transformation was a Pd(0)-catalyzed coupling of a H-phosphite with a vinyl bromide to form the desired C-P linkage. The phosphonate analogues of PtdIns(4,5)P2 were found to be effective in restoring the sensitivity of the TRPM4 channel to Ca2+ activation.
| S-EPMC2531207 | biostudies-literature
Project description:Phosphatidylinositol 3-kinases (PI3K) are divided into three classes, which differ in their substrates and products. Class I generates the inositol phospholipids PI(3)P, PI(3,4)P2, and PI(3,4,5)P3 referred as PIP, PIP2, and PIP3, respectively. Class II produces PIP and PIP2, and class III generates only PIP. Substrate and product differences of the three classes are determined by the activation loops of their catalytic domains. Substitution of the class I activation loop with either class II or III activation loop results in a corresponding change of substrate preference and product restriction. We have evaluated such activation loop substitutions to show that oncogenic activity of class I PI3K is linked to the ability to produce PIP3. We further show that reduction of cellular PIP3 levels by the 5'-phosphatase PIPP interferes with PI3K-induced oncogenic transformation. PIPP also attenuates signaling through Akt and target of rapamycin. Class III PI3K fails to induce oncogenic transformation. Likewise, a constitutively membrane-bound class I PI3K mutant retaining only the protein kinase is unable to induce transformation. We conclude that PIP3 is an essential component of PI3K-mediated oncogenesis and that inability to generate PIP3 abolishes oncogenic potential.
| S-EPMC2767251 | biostudies-literature
Project description:Phosphatidylinositol polyphosphate lipids, such as phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P?], regulate critical biological processes, many of which are aberrant in disease. These lipids often act as site-specific ligands in interactions that enforce membrane association of protein binding partners. Herein, we describe the development of bifunctional activity probes corresponding to the headgroup of PI(3,4,5)P? that are effective for identifying and characterizing protein binding partners from complex samples, namely cancer cell extracts. These probes contain both a photoaffinity tag for covalent labeling of target proteins and a secondary handle for subsequent detection or manipulation of labeled proteins. Probes bearing different secondary tags were exploited, either by direct attachment of a fluorescent dye for optical detection or by using an alkyne that can be derivatized after protein labeling via click chemistry. First, we describe the design and modular synthetic strategy used to generate multiple probes with different reporter tags of use for characterizing probe-labeled proteins. Next, we report initial labeling studies using purified protein, the PH domain of Akt, in which probes were found to label this target, as judged by in-gel detection. Furthermore, protein labeling was abrogated by controls including competition with an unlabeled PI(3,4,5)P? headgroup analogue as well as through protein denaturation, indicating specific labeling. In addition, probes featuring linkers of different lengths between the PI(3,4,5)P? headgroup and photoaffinity tag led to variations in protein labeling, indicating that a shorter linker was more effective in this case. Finally, proteomic labeling studies were performed using cell extracts; labeled proteins were observed by in-gel detection and characterized using postlabeling with biotin, affinity chromatography, and identification via tandem mass spectrometry. These studies yielded a total of 265 proteins, including both known and novel candidate PI(3,4,5)P?-binding proteins.
| S-EPMC3649876 | biostudies-literature
Project description:The mammalian tumor suppressor, phosphatase and tensin homologue deleted on chromosome 10 (PTEN), inhibits cell growth and survival by dephosphorylating phosphatidylinositol-(3,4,5)-trisphosphate (PI[3,4,5]P3). We have found a homologue of PTEN in the fission yeast, Schizosaccharomyces pombe (ptn1). This was an unexpected finding because yeast (S. pombe and Saccharomyces cerevisiae) lack the class I phosphoinositide 3-kinases that generate PI(3,4,5)P3 in higher eukaryotes. Indeed, PI(3,4,5)P3 has not been detected in yeast. Surprisingly, upon deletion of ptn1 in S. pombe, PI(3,4,5)P3 became detectable at levels comparable to those in mammalian cells, indicating that a pathway exists for synthesis of this lipid and that the S. pombe ptn1, like mammalian PTEN, suppresses PI(3,4,5)P3 levels. By examining various mutants, we show that synthesis of PI(3,4,5)P3 in S. pombe requires the class III phosphoinositide 3-kinase, vps34p, and the phosphatidylinositol-4-phosphate 5-kinase, its3p, but does not require the phosphatidylinositol-3-phosphate 5-kinase, fab1p. These studies suggest that a pathway for PI(3,4,5)P3 synthesis downstream of a class III phosphoinositide 3-kinase evolved before the appearance of class I phosphoinositide 3-kinases.
| S-EPMC2172303 | biostudies-literature
Project description:Generation of a phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P(3)] gradient within the plasma membrane is important for cell polarization and chemotaxis in many eukaryotic cells. The gradient is produced by the combined activity of phosphatidylinositol 3-kinase (PI3K) to increase PI(3,4,5)P(3) on the membrane nearest the polarizing signal and PI(3,4,5)P(3) dephosphorylation by phosphatase and tensin homolog deleted on chromosome ten (PTEN) elsewhere. Common to both of these enzymes is the lipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)], which is not only the substrate of PI3K and product of PTEN but also important for membrane binding of PTEN. Consequently, regulation of phospholipase C (PLC) activity, which hydrolyzes PI(4,5)P(2), could have important consequences for PI(3,4,5)P(3) localization. We investigate the role of PLC in PI(3,4,5)P(3)-mediated chemotaxis in Dictyostelium. plc-null cells are resistant to the PI3K inhibitor LY294002 and produce little PI(3,4,5)P(3) after cAMP stimulation, as monitored by the PI(3,4,5)P(3)-specific pleckstrin homology (PH)-domain of CRAC (PH(CRAC)GFP). In contrast, PLC overexpression elevates PI(3,4,5)P(3) and impairs chemotaxis in a similar way to loss of pten. PI3K localization at the leading edge of plc-null cells is unaltered, but dissociation of PTEN from the membrane is strongly reduced in both gradient and uniform stimulation with cAMP. These results indicate that local activation of PLC can control PTEN localization and suggest a novel mechanism to regulate the internal PI(3,4,5)P(3) gradient.
| S-EPMC2096598 | biostudies-literature
Project description:Generation of the lipid messenger phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3) is crucial for development, cell growth and survival, and motility, and it becomes dysfunctional in many diseases including cancers. Here we reveal a mechanism for PtdIns(3,4,5)P3 generation by scaffolded phosphoinositide kinases. In this pathway, class I phosphatidylinositol-3-OH kinase (PI(3)K) is assembled by IQGAP1 with PI(4)KIII? and PIPKI?, which sequentially generate PtdIns(3,4,5)P3 from phosphatidylinositol. By scaffolding these kinases into functional proximity, the PtdIns(4,5)P2 generated is selectively used by PI(3)K for PtdIns(3,4,5)P3 generation, which then signals to PDK1 and Akt that are also in the complex. Moreover, multiple receptor types stimulate the assembly of this IQGAP1-PI(3)K signalling complex. Blockade of IQGAP1 interaction with PIPKI? or PI(3)K inhibited PtdIns(3,4,5)P3 generation and signalling, and selectively diminished cancer cell survival, revealing a target for cancer chemotherapy.
| S-EPMC5679705 | biostudies-literature
Project description:Many neutrophil functions are regulated by phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3) that mediates protein membrane translocation via binding to pleckstrin homolog (PH) domains within target proteins. Here we show that inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4), a cytosolic small molecule, bound the same PH domain of target proteins and competed for binding to PtdIns(3,4,5)P3. In neutrophils, chemoattractant stimulation triggered rapid elevation in Ins(1,3,4,5)P4 concentration. Depletion of Ins(1,3,4,5)P4 by deleting the gene encoding InsP3KB, which converts Ins(1,4,5)P3 to Ins(1,3,4,5)P4, enhanced membrane translocation of the PtdIns(3,4,5)P3-specific PH domain. This led to enhanced sensitivity to chemoattractant stimulation, elevated superoxide production, and enhanced neutrophil recruitment to inflamed peritoneal cavity. On the contrary, augmentation of intracellular Ins(1,3,4,5)P4 concentration blocked PH domain-mediated membrane translocation of target proteins and dramatically decreased the sensitivity of neutrophils to chemoattractant stimulation. These findings establish a role for Ins(1,3,4,5)P4 in cellular signal transduction pathways and provide another mechanism for modulating PtdIns(3,4,5)P3 signaling in neutrophils.
| S-EPMC2084373 | biostudies-literature
Project description:Neutrophil spontaneous death plays essential roles in neutrophil homeostasis and resolution of inflammation, whereas the underlying molecular mechanisms are still ill-defined. Neutrophils die because of programmed cell death or apoptosis. However, treatment with inhibitor of caspases, which are responsible for the majority of apoptotic cell deaths, does not prevent the spontaneous death of neutrophils. PKB/Akt possesses prosurvival and antiapoptotic activities in a variety of cells. In this study, we show that Akt activity decreases dramatically during the course of neutrophil death. Both phosphatidylinositol 3-kinase and Akt inhibitors enhance neutrophil death. Conditions delaying neutrophil death, such as treatment with granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor, or IFN-gamma, restore Akt activity. Finally, we demonstrate that neutrophils depleted of PTEN, a phosphatidylinositol 3'-phosphatase that negatively regulates Akt activity, live much longer than WT neutrophils. Thus, we establish Akt deactivation as a causal mediator of neutrophil spontaneous death.
| S-EPMC1595438 | biostudies-literature
Project description:Phosphatidylinositol (3,4,5)-triphosphate (PtdInsP(3)) mediates intracellular signaling for directional sensing and pseudopod extension at the leading edge of migrating cells during chemotaxis. How this PtdInsP(3) signal is translated into remodeling of the actin cytoskeleton is poorly understood. Here, using a proteomics approach, we identified multiple PtdInsP(3)-binding proteins in Dictyostelium discoideum, including five pleckstrin homology (PH) domain-containing proteins. Two of these, the serine/threonine kinase Akt/protein kinase B and the PH domain-containing protein PhdA, were previously characterized as PtdInsP(3)-binding proteins. In addition, PhdB, PhdG, and PhdI were identified as previously undescribed PH domain-containing proteins. Specific PtdInsP(3) interactions with PhdB, PhdG, and PhdI were confirmed using an in vitro lipid-binding assay. In cells, PhdI associated with the plasma membrane in a manner dependent on both the PH domain and PtdInsP(3). Consistent with this finding, PhdI located to the leading edge in migrating cells. In contrast, PhdG was found in the cytosol in WT cells. However, when PtdInsP(3) was overproduced in pten(-) cells, PhdG located to the plasma membrane, suggesting its weak affinity for PtdInsP(3). PhdB was found to bind to the plasma membrane via both PtdInsP(3)-dependent and -independent mechanisms. The PtdInsP(3)-independent interaction was mediated by the middle domain, independent of the PH domain. In migrating cells, the majority of PhdB was found at the lagging edge. Finally, we deleted the genes encoding PhdB and PhdG and demonstrated that both proteins are required for efficient chemotaxis. Thus, this study advances our understanding of the PtdInsP(3)-mediated signaling mechanisms that control directed cell migration in chemotaxis.
| S-EPMC2900710 | biostudies-literature