Biochemical analysis of human IQGAP proteins

人类 IQGAP 蛋白的生化分析

• 批准号: BB/D000394/1
• 负责人: David Timson
• 金额: $ 23.08万
• 依托单位: Queen's University Belfast
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FD000394%2F1
• 关键词: Biochemical; analysis; human; IQGAP; proteins

In your cells there is a network of proteins called the cytoskeleton. This isn't a very good name because unlike your bones it is constantly being taken apart, put back together and moved around. Its job is to provide support for the cell, to provide tracks for things to move about in the cell on and to help the cell move around. All these activities need to be co-ordinated and if this goes wrong you'll get ill. You might even get cancer. One of the most interesting recent discoveries is that there are a group of proteins whose job it is to help organise the cytoskeleton. These organising proteins (called scaffolding proteins) do more than just bring the right proteins together at the right time. They also talk to other proteins by sticking to them. When two proteins stick to each other messages can be passed between them because of the different shapes the molecules can adopt. So we think these scaffolding proteins listen to what other proteins have to say, work out what it all means and then pass the right message on to the cytoskeleton. You can think of them being like miniature telephone exchanges. We want to know how they work. The particular scaffolding proteins we are interested in are called the IQGAP proteins. In your body you have three different types of IQGAP protein called IQGAP1, IQGAP2 and IQGAP3. Don't worry / the name IQGAP doesn't mean that you're stupid because you have a gap in your IQ. It's actually named after two parts of the protein / the IQ-motifs and the GAP domain. These are two of the bits of the protein which stick to other proteins. The IQ-motifs stick to a protein called calmodulin and the GAP domain to one called CDC42. Both calmodulin and CDC42 are proteins which carry messages round the cell. There's another bit we're interested in called the CHD which sticks to actin. Actin is a protein in the cytoskeleton. So we think IQGAPs collect information from calmodulin and CDC42 and pass it on to actin. We want to find out how they do that. What we're going do is to genetically engineer some bacteria so that they'll make calmodulin and CDC42 for us. IQGAPs are a bit big to do this with and so we'll make fragments of them. Luckily for us, other scientists have already worked out some fragments which bacteria are happy to make. We've also got a problem with actin. Other people have shown that when bacteria make this protein it doesn't work properly. So we'll make that one in yeast instead. Once we've got all these proteins we'll ask how they stick together. We'll try and find out the chemical details of what's going on at the places where the proteins stick together. Of course proteins are very very small and so we can't just look at them. We can't even look at them under a microscope. So we have to use indirect methods using chemistry and physics to find out what's going on. We're also going to find out how tightly they stick / again using chemical and physical methods. Another thing we're very interested in is how IQGAP1, IQGAP2 and IQGAP3 differ from each other. We know that they are quite similar, but we also know that IQGAP1 and IQGAP2 are found in different cells and stick to a slightly different range of other proteins. As for IQGAP3 we really don't know anything about that yet. So anything we discover about it really will be novel. We think that the way each IQGAP sticks to these other proteins will be slightly different and that how strongly they stick will also be different. Hopefully once we know the chemical details about how they stick, we'll also have a good idea about why the strength of stickiness is different. This project is important because the cytoskeleton goes wrong in a lot of diseases and some drugs interact with the cytoskeleton. When we've finished we'll be a bit closer to understanding how these tiny molecular telephone exchanges actually work.

在你的细胞中有一个蛋白质网络叫做细胞骨架。这不是一个很好的名字，因为不像你的骨头，它是不断被拆开，重新组合起来，并四处移动。它的工作是为细胞提供支持，为细胞内的物体提供轨道，并帮助细胞四处移动。所有这些活动都需要协调，如果出了问题，你会生病的。你甚至可能得癌症。最近最有趣的发现之一是，有一组蛋白质的工作是帮助组织细胞骨架。这些组织蛋白质（称为支架蛋白质）不仅仅是在正确的时间将正确的蛋白质聚集在一起。它们还通过粘附在其他蛋白质上与它们交谈。当两种蛋白质相互粘附时，由于分子可以采用不同的形状，信息可以在它们之间传递。所以我们认为这些支架蛋白会倾听其他蛋白的声音，理解它们的含义，然后将正确的信息传递给细胞骨架。你可以把它们想象成微型电话交换机。我们想知道它们是如何工作的。我们感兴趣的特殊支架蛋白被称为IQGAP蛋白。在你的身体里，有三种不同类型的IQGAP蛋白质，分别是IQGAP 1、IQGAP 2和IQGAP 3。别担心，IQGAP这个名字并不意味着你很笨，因为你的智商有差距。它实际上是以蛋白质的两个部分命名的：IQ基序和差距域。这是蛋白质中的两个片段，它们会粘附在其他蛋白质上。IQ基序附着在一种叫做钙调素的蛋白质上，差距结构域附着在一种叫做CDC 42的蛋白质上。钙调素和CDC 42都是在细胞内传递信息的蛋白质。我们感兴趣的是另一种叫做CHD的细胞，它附着在肌动蛋白上。肌动蛋白是细胞骨架中的一种蛋白质。所以我们认为IQGAP从钙调素和CDC 42收集信息并将其传递给肌动蛋白。我们想知道他们是怎么做到的。我们要做的是对一些细菌进行基因工程改造，这样它们就能为我们制造钙调素和CDC 42。IQGAP有点大，所以我们将制作它们的片段。对我们来说幸运的是，其他科学家已经研究出了一些细菌乐于制造的碎片。肌动蛋白也有问题。其他人已经证明，当细菌制造这种蛋白质时，它不能正常工作。所以我们要用酵母做。一旦我们得到了所有这些蛋白质，我们会问它们是如何粘在一起的。我们将尝试找出蛋白质结合在一起的化学细节。当然蛋白质是非常非常小的，所以我们不能只看它们。我们甚至不能在显微镜下观察它们。所以我们必须用化学和物理的间接方法来找出发生了什么，我们也要用化学和物理的方法来找出它们粘得有多紧。另一件我们非常感兴趣的事情是IQGAP 1，IQGAP 2和IQGAP 3之间的区别。我们知道它们非常相似，但我们也知道IQGAP 1和IQGAP 2存在于不同的细胞中，并且与其他蛋白质的粘附范围略有不同。至于IQGAP 3，我们还真的不知道。所以我们发现的任何东西都是新奇的。我们认为，每种IQGAP与其他蛋白质的粘附方式略有不同，它们的粘附强度也有所不同。希望一旦我们知道了它们如何粘附的化学细节，我们也会很好地了解为什么粘性的强度不同。这个项目很重要，因为在许多疾病中细胞骨架会出现问题，一些药物会与细胞骨架相互作用。当我们完成后，我们将更接近了解这些微小的分子电话交换机实际上是如何工作的。

项目成果

On the Interaction Between Human IQGAP1 and Actin.

• DOI: 10.2174/0929866523666160204123331
• 发表时间: 2016-03
• 期刊: Protein and peptide letters
• 影响因子: 1.6
• 作者: Damian J. Magill;Elaine Hamilton;S. Shirran;C. Botting;D. Timson

IQGAP1 Interaction with RHO Family Proteins Revisited: KINETIC AND EQUILIBRIUM EVIDENCE FOR MULTIPLE DISTINCT BINDING SITES.

• DOI: 10.1074/jbc.m116.752121
• 发表时间: 2016-12-16
• 期刊: The Journal of biological chemistry
• 作者: Nouri K;Fansa EK;Amin E;Dvorsky R;Gremer L;Willbold D;Schmitt L;Timson DJ;Ahmadian MR
• 通讯作者: Ahmadian MR

New model for the interaction of IQGAP1 with CDC42 and RAC1.

• DOI: 10.1080/21541248.2017.1321169
• 发表时间: 2020-01-01
• 期刊: Small GTPases
• 作者: Nouri, Kazem;Timson, David J;Ahmadian, Mohammad R
• 通讯作者: Ahmadian, Mohammad R

LGR5 receptor promotes cell-cell adhesion in stem cells and colon cancer cells via the IQGAP1-Rac1 pathway.

• DOI: 10.1074/jbc.m117.786798
• 发表时间: 2017-09-08
• 期刊: The Journal of biological chemistry
• 作者: Carmon KS;Gong X;Yi J;Wu L;Thomas A;Moore CM;Masuho I;Timson DJ;Martemyanov KA;Liu QJ
• 通讯作者: Liu QJ

IQ-motif selectivity in human IQGAP2 and IQGAP3: binding of calmodulin and myosin essential light chain

• DOI: 10.1042/bsr20100123
• 发表时间: 2011-10-01
• 期刊: BIOSCIENCE REPORTS
• 影响因子: 4
• 作者: Atcheson, Erwan;Hamilton, Elaine;Timson, David J.
• 通讯作者: Timson, David J.