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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Ras is an indispensable coregulator of the class I_B phosphoinositide 3-kinase p87/p110γ
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Ras is an indispensable coregulator of the class I_B phosphoinositide 3-kinase p87/p110γ

机译:Ras是I_B磷酸肌醇3激酶p87 /p110γ必不可少的调节剂

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摘要

Class I_B phosphoinositide 3-kinase γ (PI3K_γ) elicits various immu-nologic and cardiovascular responses; however, the molecular basis for this signal heterogeneity is unclear. PI3K_γ consists of a catalytic p110_γ and a regulatory p87~(PIKAP) (p87, also p84) or p101 subunit. Hitherto p87 and p101 are generally assumed to exhibit redundant functions in receptor-induced and G protein β_γ (Gβ_γ)-mediated PI3K_γ regulation. Here we investigated the molecular mechanism for receptor-dependent p87/p110_γ activation. By analyzing GFP-tagged proteins expressed in HEK293 cells, PI3K_γ-complemented bone marrow-derived mast cells (BMMCs) from p110_γ~(-1-) mice, and purified recombinant proteins reconstituted to lipid vesicles, we elucidated a novel pathway of p87-dependent, G protein-coupled receptor (GPCR)-induced PI3Ky activation. Although p101 strongly interacted with Gβ_γ, thereby mediating PI3K_γ membrane recruitment and stimulation, p87 exhibited only a weak interaction, resulting in modest kinase activation and lack of membrane recruitment. Surprisingly, Ras-GTP substituted the missing Gβ_γ-dependent membrane recruitment of p87/p110_γ by direct interaction with p110_γ, suggesting the indispensability of Ras for activation of p87/p110_γ. Consequently, interference with Ras signaling indeed selectively blocked p87/p110_γ, but not p101/ p110_γ, kinase activity in HEK293 and BMMC cells, revealing an important crosstalk between monomeric and trimeric G proteins for p87/p110_γ activation. Our data display distinct signaling requirements of p87 and p101, conferring signaling specificity to PI3K_γ that could open up new possibilities for therapeutic intervention.
机译:I_B类磷酸肌醇3激酶γ(PI3K_γ)引发各种免疫和心血管反应。但是,这种信号异质性的分子基础尚不清楚。 PI3K_γ由催化性p110_γ和调节性p87〜(PIKAP)(p87,也称为p84)或p101亚基组成。迄今为止,通常假定p87和p101在受体诱导的和G蛋白β_γ(Gβ_γ)介导的PI3K_γ调节中显示出冗余功能。在这里,我们研究了受体依赖性p87 /p110_γ激活的分子机制。通过分析在HEK293细胞,p110_γ〜(-1-)小鼠中PI3K_γ互补的骨髓肥大细胞(BMMCs)中表达的GFP标记蛋白以及重构为脂质囊泡的纯化重组蛋白,我们阐明了p87-依赖的G蛋白偶联受体(GPCR)诱导的PI3Ky激活。尽管p101与Gβ_γ强烈相互作用,从而介导PI3K_γ膜募集和刺激,但p87仅表现出弱相互作用,导致适度的激酶活化和膜募集的缺乏。令人惊讶的是,Ras-GTP通过与p110_γ直接相互作用替代了缺失的依赖于Gβ_γ的p87 /p110_γ膜募集,表明Ras激活p87 /p110_γ不可或缺。因此,对Ras信号的干扰确实选择性地阻断了HEK293细胞和BMMC细胞中的p87 /p110_γ激酶活性,但没有阻断p101 /p110_γ激酶活性,揭示了单体和三聚体G蛋白之间对于p87 /p110_γ活化的重要串扰。我们的数据显示p87和p101具有不同的信号传导要求,赋予PI3K_γ信号传导特异性,这可能为治疗干预开辟新的可能性。

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  • 作者单位

    Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Pharmaceutical Research, University of Tubingen, 72074 Tubingen, Germany Institute of Biochemistry and Molecular Biology II, Heinrich Heine University Hospitals and Clinics, 40225 Dusseldorf, Germany;

    Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Pharmaceutical Research, University of Tubingen, 72074 Tubingen, Germany Institute of Biochemistry and Molecular Biology II, Heinrich Heine University Hospitals and Clinics, 40225 Dusseldorf, Germany;

    Institute of Biochemistry and Genetics, Deparment of Biomedicine, University of Basel, CH-4051 Basel, Switzerland;

    Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Pharmaceutical Research, University of Tubingen, 72074 Tubingen, Germany Institute of Biochemistry and Molecular Biology II, Heinrich Heine University Hospitals and Clinics, 40225 Dusseldorf, Germany;

    Institute of Pharmacology, Free University of Berlin, 14195 Berlin, Germany Splicos, 34090 Montpellier, France;

    Institute of Biochemistry and Molecular Biology II, Heinrich Heine University Hospitals and Clinics, 40225 Dusseldorf, Germany;

    Institute of Pharmacology, Free University of Berlin, 14195 Berlin, Germany Rudolf Boehm Institute of Pharmacology and Toxicology, University of Leipzig, 04109 Leipzig, Germany;

    Institute of Biochemistry and Molecular Biology II, Heinrich Heine University Hospitals and Clinics, 40225 Dusseldorf, Germany Institute of Pharmacology and Toxicology and Rudolf Virchow DFG Research Center for Experimental Biomedicine, University of Wurzburg, 97070 Wurzburg, Germany;

    Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Pharmaceutical Research, University of Tubingen, 72074 Tubingen, Germany;

    Institute of Biochemistry and Genetics, Deparment of Biomedicine, University of Basel, CH-4051 Basel, Switzerland;

    Institute of Biochemistry and Molecular Biology II, Heinrich Heine University Hospitals and Clinics, 40225 Dusseldorf, Germany Institute of Pharmacology and Toxicology and Rudolf Virchow DFG Research Center for Experimental Biomedicine, University of Wurzburg, 97070 Wurzburg, Germany;

    Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Pharmaceutical Research, University of Tubingen, 72074 Tubingen, Germany Institute of Biochemistry and Molecular Biology II, Heinrich Heine University Hospitals and Clinics, 40225 Dusseldorf, Germany Institute of Pharmacology, Free University of Berlin, 14195 Berlin, Germany;

  • 收录信息 美国《科学引文索引》(SCI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    confocal life cell imaging; G protein; receptor signaling; mast cells;

    机译:共聚焦活细胞成像;G蛋白;受体信号;肥大细胞;

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