About this Research Topic
Biomembranes act as a central interface between cells and their surrounding as well as between different cellular compartments within cells. Key components, i.e. transport and receptor proteins, control developmental processes, transport of nutrients and molecules, sensing and signal transduction, cell-cell communication, cellular trafficking of cargo, and metabolic processes. It is increasingly recognized that the understanding of these processes is also directly linked to the complex interplay between membrane proteins and their lipid environment. Biochemical and genetic studies of membrane proteins have yielded many insights into their functions but molecular analysis of these proteins has historically been hampered by the challenges of gaining high-resolution structural information from integral membrane proteins.
In recent years there has been progress in the structural analysis of membrane proteins and an exponential growth in the number of membrane protein structures determined. More than 2,000 membrane protein structures are now known, which is a very small proportion of all determined protein structures that does neither reflect the biological importance of membrane proteins, nor their proportions in prokaryotic and eukaryotic genomes. Noteworthy, many of the deposited membrane protein structures have been determined without a lipid bilayer environment and are predominantly from bacterial origin, with relatively few from multicellular eukaryotes including plants. These aspects may introduce a bias in our understanding of membrane signalling and/or impede data interpretation for eukaryotic systems.
An improved structural understanding of (plant) membrane proteins, including those at the mitochondrial and chloroplast membranes, will advance understanding of many fundamental (plant) processes, and will be beneficial to applications of plant biology in agriculture, nutrition, plant-environmental interactions and plant biotechnology. For instance, plant-microbial interactions are controlled by cell-cell recognition, interaction, and communication, but many of these processes are poorly understood on a protein structural basis.
While many atomic resolution structures have been gained through the use of X-ray crystallography, a fundamental limitation is the challenge of crystallising membrane proteins. Recent advances in solution and single-particle methods such as cryo-electron microscopy, nuclear magnetic resonance and small angle scattering have allowed structural data to be obtained in the absence of diffracting crystals. Furthermore, computational modelling methods are enabling greater prediction of membrane protein structures in isolation and in lipid environments or in association with ligands and other associated proteins. The structural biology of membrane proteins is still a challenging endeavour but new insights and developments are being constantly made.
This research topic will present reviews, opinions and original research on the structural and functional characteristics of membrane transport and receptor proteins from different cellular compartments and organisms, with a focus on plant proteins, including chloroplast and mitochondrial proteins, and plant-biotic interactions. Additionally, it features advances in membrane methodology, including membrane mimetics and new techniques to obtain high-resolution structural insights in increasingly native environments. Contributions of the latest research in the field of membrane protein structural biology as well as method developments and technology applications are encouraged.
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