CELLS

Cells

Cells

Introduction

This paper intends to describe how transient protein interactions can contribute to direct information flow between subsequent steps of metabolic and signaling pathways, focusing on the redox perspective. Posttranslational modifications are often the basis for the dynamic nature of such macromolecular aggregates, named micro compartments. The high cellular protein concentration promotes these interactions that are prone to disappear upon the extraction of proteins from cells. Changes of signaling molecules, such as metabolites, effectors or phytohormones, or the redox state in the cellular microenvironment, can modulate them. The signaling network can, therefore, respond in a very flexible and appropriate manner, such that metabolism, stress responses, and developmental steps are integrated by multiple and changing contacts between functional modules. The purpose of this paper is to make the reader aware that we did the experiment in the lab n basically we meant to write all we know about cells and any information about cells (www.ncbi.nlm.nih.gov).

Method

Micro compartments often depend on weak protein-protein interactions in their defined cellular microenvironments. Here, they are suggested to be involved in the formation, transduction and execution in redox-signaling processes, particularly in view of their interaction with other signaling cascades. About 10 years ago, research on MAP kinase pathways opened up a new, productive field in understanding plant signal transduction. It was shown that posttranslational protein modification by phosphorylation plays a pivotal role in two-component systems and MAPK signaling cascades leading to a range of cellular responses during both plant stress and development. Thio switches are now emerging as additional posttranslational modifications encountered in signal transduction. There is newly emerging evidence for redox-dependent steps acting on phosphorylation cascades of signal transduction (www.biology 4kids.com).

Cells

The capacity for rapid and dynamic changes in affinity between molecules means that transient complexes are highly suited for information transfer, as well as forming ' channels' for metabolic pathways. Redox imbalances as signals to maintain homeostasis Redox homeostasis is one of the basic requirements of a cell, and deviation from a balanced redox state is indicative of disturbances. Therefore, it is assumed that any imbalance leading to the formation of reactive oxygen/ nitrogen species (ROS/RNS) might serve as a signal. Indeed, upon stress, e.g., due to sudden exposure to high light, plants can respond at different levels. They are capable to rapidly adjust to changed electron fluxes, as well as to induce gene expression for long-term adaptation at the transcriptional level.

In order to achieve the latter, imbalances in the electron transport chains of chloroplasts or mitochondria (as central pathways of energy-converting reactions) must initiate signaling processes that are finally perceived in the nucleus, resulting in altered gene expression of organelle-localized proteins. For these studies, transgenic approaches have been used that helped to discover new parts of the complex signaling system. Such a scenario is known as retrograde signaling. Additional factors also impact on plant cells, such as other abiotic factors, pathogens, or morphogenic gradients over cells for determining the coordinated development of cells within tissues. Stress can result in oxidative bursts through plasma membrane NADPH oxidases ...