Collaborative Proposal to Examine the Function and

生物学的一个基本问题是如何使生物体达到适当的尺寸。组织和器官的大小是细胞大小和数量的结果，并受外在信号（如胰岛素肽）和内在细胞信号（测量营养和环境输入）的控制。这个研究项目将利用一种遗传模式生物来了解细胞分裂是如何通过一个名为tribles的基因的作用来平衡细胞生长的。tribles在所有动物体内都存在，在人类中，它与癌症和2型糖尿病有关，但人们对它的功能知之甚少。已有研究表明，Tribbles通过结合Cdc25蛋白（分裂的关键触发因子）阻止细胞分裂，以及(2)通过结合Akt激酶蛋白来抑制胰岛素刺激的细胞生长。这个研究项目将阐明Tribbles在动物发育过程中调节大小的功能，并将对研究Tribbles在人类疾病中的作用的科学家产生影响。该研究计划还将支持正在进行的努力，以培养学生在分子和细胞生物学的方法，解剖保守的发展机制的模式生物。这些关于Trbl在细胞生长和增殖中的保守作用的研究将有助于深入了解动物多样性的遗传基础、进化机制、环境条件对发育程序的影响以及发育异常和代谢疾病的潜在原因。在亲缘关系密切的动物物种之间，身体大小的差异令人印象深刻，而物种特有的适应，如哺乳动物的前肢和昆虫的特殊头部，显示出令人难以置信的尺寸缩放。体型受到强烈的进化选择压力的影响，包括配偶选择、捕食和对环境变化的耐受性，此外，动物根据营养物质的可用性和一系列环境因素（包括温度和氧气水平）来调整体型。协调这种发育可塑性的机制尚不完全清楚，包括激素信号、生长因子和胰岛素样肽的整合，以确保生长所需的能量与摄入的能量相匹配。Tribbles激酶（Trbl）结合并阻断许多调节细胞生长、分裂和分化的关键靶点，特别是抑制细胞增殖的cdc25磷酸酶和抑制胰岛素刺激的细胞生长和代谢的Akt激酶。Trbl是一种保守的接头蛋白，它调节细胞增殖（通过结合和降解Cdc25）和细胞大小（通过结合和抑制Akt）对饮食的反应，这一观点将在三个方面得到验证：(1)探索Trbl在正常和饮食应激下细胞生长中的作用；(2)对Trbl进行结构/功能分析，重点分析其保守特征；以及(3)通过(a)酵母两种杂交筛选和(b)使用Trbl特异性抗血清进行共同免疫下拉筛选与Trbl物理相互作用的蛋白质。

A fundamental problem in biology is how the proper size of an organism is achieved. The size of tissues and organs is a consequence of both cell size and number and is controlled by both extrinsic signals, such as insulin peptides, and intrinsic cell signals that measure nutritional and environmental inputs. This research program will exploit a genetic model organism to understand how cell division is balanced by cell growth by the action of a gene named Tribbles. Tribbles is found in all animals, and in humans it has been connected to cancer and Type 2 diabetes, but its functions are poorly understood. It has been shown that Tribbles blocks: (1) cell division by binding the protein Cdc25, a key trigger of division, and (2) insulin-stimulated cell growth by binding the protein Akt kinase. This research program will shed light on the functions of Tribbles that regulate animal size during development, and will have implications for scientists studying the role of Tribbles in human disease. The research program will also support ongoing efforts to train students in molecular and cell biological approaches to dissect conserved developmental mechanisms in a model organism.These studies of the conserved role of Trbl in cell growth and proliferation will offer insight into the genetic basis of animal diversity, the mechanism of evolution, the effect of environmental conditions on a developmental program, and the underlying causes of developmental aberrations and metabolic disease. Body sizes vary impressively between closely related animal species, and species-specific adaptations, such as the mammalian forelimb and specialized head segments among insects, show incredible size scaling. Size is subject to intense evolutionary selection pressure with consequences for mate selection, predation and tolerance to environmental changes, moreover animals adjust size to both nutrient availability and a host of environmental cues including temperature and O2 levels. The mechanisms coordinating this developmental plasticity are incompletely understood, and include integration of cues from hormonal signals, growth factors and insulin-like peptides to ensure that energy expended on growth matches energy intake. The kinase Tribbles (Trbl) binds and blocks a number of key targets that regulate cell growth, division and differentiation, notably cdc25 phosphatase to inhibit cell proliferation and Akt kinase to inhibit insulin-stimulated cell growth and metabolism. The notion that Trbl is an conserved adaptor protein that regulates both cell proliferation (by binding and degrading Cdc25) and cell size (by binding and inhibiting Akt) in response to diet will be tested in three aims: (1) to explore the role of Trbl in cell growth during normal and dietary stress; (2) to perform a structure/function analysis of Trbl, focused on its conserved features; and (3) to conduct a screen for proteins that physically interact with Trbl by (a) yeast two hybrid screens and (b) co-immuno-pulldown using Trbl-specific antisera.