Alam-Nazki Aiman, Krishnan J
Centre for Process Systems Engineering, Department of Chemical Engineering, South Kensington Campus, London, SW7 2AZ, UK.
BMC Syst Biol. 2012 Jul 5;6:83. doi: 10.1186/1752-0509-6-83.
Spatial signal transduction plays a vital role in many intracellular processes such as eukaryotic chemotaxis, polarity generation and cell division. Furthermore it is being increasingly realized that the spatial dimension to signalling may play an important role in other apparently purely temporal signal transduction processes. It is increasingly being recognized that a conceptual basis for studying spatial signal transduction in signalling networks is necessary.
In this work we examine spatial signal transduction in a series of standard motifs/networks. These networks include coherent and incoherent feedforward, positive and negative feedback, cyclic motifs, monostable switches, bistable switches and negative feedback oscillators. In all these cases, the driving signal has spatial variation. For each network we consider two cases, one where all elements are essentially non-diffusible, and the other where one of the network elements may be highly diffusible. A careful analysis of steady state signal transduction provides many insights into the behaviour of all these modules. While in the non-diffusible case for the most part, spatial signalling reflects the temporal signalling behaviour, in the diffusible cases, we see significant differences between spatial and temporal signalling characteristics. Our results demonstrate that the presence of diffusible elements in the networks provides important constraints and capabilities for signalling.
Our results provide a systematic basis for understanding spatial signalling in networks and the role of diffusible elements therein. This provides many insights into the signal transduction capabilities and constraints in such networks and suggests ways in which cellular signalling and information processing is organized to conform to or bypass those constraints. It also provides a framework for starting to understand the organization and regulation of spatial signal transduction in individual processes.
空间信号转导在许多细胞内过程中起着至关重要的作用，如真核生物趋化性、极性产生和细胞分裂。此外，人们越来越意识到信号转导的空间维度可能在其他明显纯粹的时间信号转导过程中发挥重要作用。人们越来越认识到，研究信号网络中空间信号转导的概念基础是必要的。
在这项工作中，我们研究了一系列标准基序/网络中的空间信号转导。这些网络包括相干和非相干前馈、正反馈和负反馈、循环基序、单稳态开关、双稳态开关和负反馈振荡器。在所有这些情况下，驱动信号都具有空间变化。对于每个网络，我们考虑两种情况，一种是所有元件基本上不可扩散，另一种是网络元件之一可能高度可扩散。对稳态信号转导的仔细分析为所有这些模块的行为提供了许多见解。虽然在大多数不可扩散的情况下，空间信号转导反映了时间信号转导行为，但在可扩散的情况下，我们看到空间和时间信号转导特征之间存在显著差异。我们的结果表明，网络中可扩散元件的存在为信号转导提供了重要的限制和能力。
我们的结果为理解网络中的空间信号转导及其可扩散元件在其中的作用提供了系统的基础。这为这类网络中的信号转导能力和限制提供了许多见解，并提出了细胞信号转导和信息处理如何组织以符合或绕过这些限制的方式。它还提供了一个框架，开始理解个体过程中空间信号转导的组织和调节。
