Intercellular signaling during terminal differentiation

终末分化过程中的细胞间信号传导

• 批准号: 7628333
• 负责人: WILLIAM F LOOMIS
• 金额: $ 25.4万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-26 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7628333
• 关键词: Accounting; Acyl Coenzyme A; Affect; Affinity; Amino Acids; Antibodies; Aspartate; Benzodiazepine Receptor; Binding; Biological Assay; C-terminal; Cells; Chloride Channels; Cleaved cell; Communication; Complex; Coupled; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Diagnosis; Diazepam; Diazepam Binding Inhibitor; Dictyostelium; Dictyostelium discoideum; Disease; Drug usage; Encapsulated; Endosomes; Enzymes; Evolution; Exocytosis; Foundations; G-Protein-Coupled Receptors; GABA Agonists; GABA Receptor; GTP-Binding Proteins; Generations; Glutamate Decarboxylase; Glutamates; Hand; Histidine; Homologous Gene; Human; Knock-out; Ligand Binding; Light; Mammals; Membrane; Membrane Fusion; N-terminal; Neuraxis; Neuropeptides; Neurotransmitters; Null Lymphocytes; Organism; Pathway interactions; Peptide Hydrolases; Peptide Signal Sequences; Peptides; Peripheral; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Process; Production; Protease Domain; Proteins; Proteolytic Processing; Recombinants; Research Personnel; Signal Transduction; Site-Directed Mutagenesis; Surface; System; Testing; Time; Vesicle; Work; Yeasts; cell type; diazepam-binding inhibitor receptor; extracellular; gamma-Aminobutyric Acid; inorganic phosphate; insight; intercellular communication; mutant; nervous system disorder; neuropsychiatry; phosphoric diester hydrolase; promoter; protein-histidine kinase; receptor; response; Accounting; Acyl Coenzyme A; Affect; Affinity; Amino Acids; Antibodies; Aspartate; Benzodiazepine Receptor; Binding; Biological Assay; C-terminal; Cells; Chloride Channels; Cleaved cell; Communication; Complex; Coupled; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Diagnosis; Diazepam; Diazepam Binding Inhibitor; Dictyostelium; Dictyostelium discoideum; Disease; Drug usage; Encapsulated; Endosomes; Enzymes; Evolution; Exocytosis; Foundations; G-Protein-Coupled Receptors; GABA Agonists; GABA Receptor; GTP-Binding Proteins; Generations; Glutamate Decarboxylase; Glutamates; Hand; Histidine; Homologous Gene; Human; Knock-out; Ligand Binding; Light; Mammals; Membrane; Membrane Fusion; N-terminal; Neuraxis; Neuropeptides; Neurotransmitters; Null Lymphocytes; Organism; Pathway interactions; Peptide Hydrolases; Peptide Signal Sequences; Peptides; Peripheral; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Process; Production; Protease Domain; Proteins; Proteolytic Processing; Recombinants; Research Personnel; Signal Transduction; Site-Directed Mutagenesis; Surface; System; Testing; Time; Vesicle; Work; Yeasts; cell type; diazepam-binding inhibitor receptor; extracellular; gamma-Aminobutyric Acid; inorganic phosphate; insight; intercellular communication; mutant; nervous system disorder; neuropsychiatry; phosphoric diester hydrolase; promoter; protein-histidine kinase; receptor; response

DESCRIPTION (provided by applicant): Communication between prespore and prestalk cells coordinates terminal differentiation in Dictyostelium discoideum. The signals include a 34 amino acid peptide, SDF-2, that has a sequence related to that of the neuropeptide DBI (Diazepam Binding Inhibitor). The neurotransmitter GABA is also used as a signal in Dictyostelium by acting through a G-protein coupled receptor similar to the GABAB receptor of mammals. The SDF-2 receptor, DhkA, on the other hand, is a "two-component" histidine kinase completely unrelated to the DBI receptors, GABAA and "peripheral type" BZ receptors. It seems that intercellular signals have been conserved over long periods of evolution while the receptors have changed in some cases. We will further elucidate the detailed mechanisms of intercellular signaling in this genetically tractable system since the results appear to have bearing on signaling in the mammalian central nervous system and may shed light on mechanisms underlying neuropsychiatric disorders. There is a complicated interchange of information between prespore and prestalk cells as they prepare to encapsulate and vacuolize, respectively. SDF-2 is generated by proteolytic processing of a protein, AcbA, released from prespore cells. Processing occurs on the surface of prestalk cells after priming by low levels of SDF-2 or by GABA. Prespore cells respond to priming by rapid release of AcbA from vesicles. AcbA is an acyl-CoA binding protein as is the precursor of DBI. Using site-directed mutagenesis we will determine whether this activity is essential for accumulation of AcbA in endosomes and subsequent release. We will determine whether exocytosis in response to either low levels of SDF-2 or GABA is dependent on signaling through the cAMP dependent protein kinase PKA. Extracellular AcbA is proteolytically cleaved by the membrane embedded prestalk specific protease TagC, which is only exposed following priming by either low levels of SDF-2 or GABA. We will determine whether this process is also dependent on PKA activity. Our results suggest that the precursor of the mammalian neuropeptide DBI, ACBP, may be synthesized in one cell type, stored in vesicles, and processed to the active peptides by another cell type. Such interactions could modulate the levels of this natural ligand that binds at the target of the widely used drug diazepam (Valium). Our observations that GABA appears to induces rapid exocytosis not only accounts for its priming activity in Dictyostelium but provides a test system for better understanding of the basic processes controlling exocytosis. Together these studies will add to the foundation for improvements in the diagnosis and treatment of neurological diseases.

描述（由申请人提供）：前孔和prestalk细胞之间的通信协调迪斯特尔迪斯特尔的最终分化。这些信号包括34个氨基酸肽SDF-2，该氨基酸肽具有与神经肽DBI（地西epam结合抑制剂）相关的序列。神经递质GABA还通过与哺乳动物的GABAB受体相似的G蛋白偶联受体作用，用作DICTYOSTELIUM中的信号。另一方面，SDF-2受体DHKA是与DBI受体，GABAA和“外周型” BZ受体完全无关的“两组分”组氨酸激酶。在某些情况下，受体发生了变化，而受体发生了变化，看来细胞间信号已经保存了。我们将进一步阐明该遗传处理系统中细胞间信号传导的详细机制，因为结果似乎与哺乳动物中枢神经系统中的信号有关，并可能阐明神经精神疾病的机制。在准备分别封装和吸尘时，预孔和普雷斯克细胞之间存在复杂的信息互换。 SDF-2是通过从前细胞释放的蛋白质ACBA的蛋白水解加工而产生的。加工在通过低水平的SDF-2或通过GABA启动后，发生在Prestalk细胞的表面上。前细胞通过从囊泡中快速释放ACBA来应对启动。 ACBA是一种酰基-COA结合蛋白，与DBI的前体一样。使用位置定向的诱变，我们将确定此活动对于内体中ACBA的积累和随后释放是否至关重要。我们将确定响应低水平的SDF-2或GABA的胞吐作用取决于通过cAMP依赖蛋白激酶PKA信号传导。细胞外ACBA被膜嵌入的PRESTALK特异性蛋白酶TAGC蛋白水解裂解，仅在低水平的SDF-2或GABA启动后才暴露出来。我们将确定此过程是否还取决于PKA活动。我们的结果表明，可以在一种细胞类型中合成哺乳动物神经肽DBI ACBP的前体，储存在囊泡中，并通过另一种细胞类型处理为活性肽。这种相互作用可以调节这种天然配体的水平，该天然配体在广泛使用的药物地西ep（valium）的靶标上结合。我们的观察结果是，GABA似乎诱导了快速的胞吐作用，不仅说明了其在Dictyostelium中的启动活性，而且提供了一个测试系统，以更好地理解控制胞吐作用的基本过程。这些研究将加在一起为改善神经系统疾病的诊断和治疗的基础。