Mechanistic basis for co-operativity in kinesin-1 / cargo recognition

细胞拥有许多特殊的部件，这些部件必须在正确的时间出现在正确的位置，才能完成它们的功能。使用后，这些部件必须被运走以进行回收或降解。这些运输过程的错误调节或中断可能导致许多人类疾病，从阿尔茨海默病等神经退行性疾病到癌症，甚至导致艾滋病毒-1病毒感染或沙门氏菌等细菌感染。为了移动组件，细胞使用一个由被称为微管网络的电缆网络组成的运输系统。就像铁路网一样，这些电缆将细胞的各个区域连接在一起。细胞拥有沿着这个被称为分子马达的网络传播的工具，我们提出的研究马达Kinesin-1是其中最重要的一个。这些马达可以选择性地附着在细胞组件上，并在微管网络上移动它们。它们还可以通过相互滑动来控制网络本身的组织。尽管它们在细胞生物学的许多领域都很重要，但我们对这些马达如何识别它们携带的货物以及如何反过来控制马达的行为缺乏适当的了解。这项联合建议源于目前在布里斯托尔大学生物化学学院的Dodding小组和伦敦国王学院兰德尔细胞和分子生物物理中心的Steiner小组之间持续成功的合作伙伴关系。到目前为止，他们卓有成效的合作工作突出了Kinesin-1如何附着到其携带的细胞组件上(通过蛋白质-肽相互作用)以及这些连接如何反过来控制Kinesin-1移动的重要方面。重要的是，他们利用这一知识来识别小分子(类似药物的化学物质)，使我们第一次能够在细胞中直接操纵这一系统。这些令人兴奋的发现现在促进了一系列新的问题，这些问题将在这里得到解决。到目前为止，我们的研究主要集中在定义Kinesin-1和它的货物之间非常简单和直接的联系。然而，越来越明显的是，这只是情况的一部分，这个过程需要Kinesin-1和它的货物之间的多个连接，这些连接一起工作。我们认为，这些“合作”连接的确切性质决定了运输的运作方式。在这里，我们将探索Kinesin-1如何(通过附着到膜脂)直接与膜结合细胞器的表面相互作用，以及这些连接如何与我们已经定义的连接一起工作。此外，蛋白质集合可以相互作用，并与Kinesin-1相互作用--我们将寻求在分子水平上定义这些联系。我们将继续利用我们获得的知识来进一步对这个货物附着系统进行化学操作，看看我们是否可以针对Kinesin-1功能的特定方面。从长远来看，这可能表明我们可以开发针对人类疾病的激动素-1的药物。

Cells possess many specialised components that must be in the right place at the right time to fulfil their function. After their use, these components must be transported away for recycling or degradation. Mis-regulation or disruption of these transport processes can contribute to many human diseases ranging from neurodegenerative conditions such as Alzheimer's disease to cancer and even contribute to viral infections by HIV-1 or bacterial infections such as Salmonella. To move components around, cells use a transport system composed of a network of cables known as the microtubule network. Much like a railway network, these cables link together regions of the cell. Cells possess vehicles that travel along this network known as molecular motors, of which our proposed motor of study, kinesin-1, is one of the most important. These motors can selectively attach to cellular components and move them on the microtubule network. They can also control the organisation of the network itself by sliding against one another. Despite their importance across so many areas of cell biology, we lack a proper understanding of how these motors recognise the cargo that they carry and how this in turn controls the behaviour of the motor. This joint proposal stems from a sustained successful partnership between the Dodding group, now at the School of Biochemistry of the University of Bristol and the Steiner group of the Randall Centre of Cell and Molecular Biophysics, King's College London. To date, their fruitful collaborative work has highlighted important aspects of how kinesin-1 attaches to the cellular components it carries (using protein-peptide interactions) and how these connections in turn control how kinesin-1 moves. Importantly, they have used this knowledge to identify small molecules (drug-like chemicals) that have allowed us to directly manipulate this system in cells for the first time. These exciting findings have now promoted a series of new questions that will be addressed here. Until now, our studies have focused on defining quite simple and straightforward connections between kinesin-1 and its cargoes. However, it is becoming clear that this is only part of the picture and that this process requires multiple connections between kinesin-1 and its cargoes that work together. We propose that the precise nature of these 'co-operative' connections determines how transport works. Here we will explore how kinesin-1 can interact directly with the surface of membrane bound organelles (by attaching to membrane lipids) and how these connections work together with those we have already defined. Moreover, collections of proteins can interact with each other and kinesin-1 - we will seek to define those connections on a molecular level. We will continue to use the knowledge we acquire to further chemically manipulate this cargo attachment system to see if we can target specific aspects of kinesin-1 function. It is possible that in the long term, this may show how we can develop drugs to target kinesin-1 in human disease.