To optimize their growth and survival, plants perceive and respond to ultraviolet-B (UV-B) radiation. However, neither the molecular identity of the UV-B photoreceptor nor the photoperception mechanism is known. Here we show that dimers of the UVR8 protein perceive UV-B, probably by a tryptophan-based mechanism. Absorption of UV-B induces instant monomerization of the photoreceptor and interaction with COP1, the central regulator of light signaling. Thereby this signaling cascade controlled by UVR8 mediates UV-B photomorphogenic responses securing plant acclimation and thus promotes survival in sunlight.

http://science.sciencemag.org/content/sci/332/6025/103.full.pdf

Perception of UV-B by the arabidopsis UVR8 protein

INTRODUCTION . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 PHYSIOLOGICAL ROLE OF THE PROTON PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Suggested Functions... . . . . . . . .. . . . . . ... . . . . . . . . . . . . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . 62 Evidence from Studies with Yeast Mutants . . . . . . . . . . . . . . . . .... . . . . . . . ...... . . . 63 Relationship Between H+ -ATPase and K+ Transport . . . . . . . . . . . . . . ... . . .. . . . . . . . . . .. . . . . . 64 REGULATION OF PLASMA MEMBRANE ATPase ACTIVITy . . . . . . . . . . . . . . . . . . . . . . . . . 65 Factors Modulating ATPase activity . . . . . . . . . . . . . ..... . . . . ..... . . . . . . . . . . . ... . . . . . . . . .. . . . . . . . 65 Possible Regulation by Protein Kinases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . 66 Transplasmalemma Redox Activity and the H+ -ATPase . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . 69 STRUCTURE AND MECHANISM OF (E-P) ATPases . . . . .. . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . 69 Evolutionary Relationships . . . . ..... . . . . . . . .. . . .. . ... . . . . . .... . . . . . . . . . . . . . .. .. . . . . . . . . . . .. . . . . . 69 Alignment of ATPase Sequences Based on Structure Prediction . . . . ... . . ... . . . . . . . . . . . . 7 1 Functional Domains . .. . . .. . . . . ... . .. . . . .. . . . . . . . . . . . . . . . . .. . . . . ..... . . . . . .. . . . . . . . .. . . . . . . . . . . . . . 80 Coupling Mechanism . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . .... . . 86 SUMMARY AND PERSPECTIVES . . . . . . . . . . ..... . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . .. 88

Structure and Function of Plasma Membrane ATPase

Phospholipid signalling in plants

The purpose of this review is to delineate the ubiquitous and pivotal role of Ca2+ in diverse physiological processes. Emphasis will be given to the role of Ca2+ in stimulus-response coupling. In addition to reviewing the present status of research, our intention is to critically evaluate the existing data and describe the newly developing areas of Ca2+ research in plants.

Calcium messenger system in plants

CASCADE SYSTEMS AS REGULATORY DEVICES 74 PHOSPHORYLATION OF PROTEINS IN PLANT ORGANELLES ....... 75 Nuclei 75 Plastids and Mitochondria 77 Microsomal Membranes 79 PHOSPHORYLATION OF ENZYMES .. 81 Regulation of Enzyme Activities 81 Modifications of Regulatory Properties......... 84 PROTEIN PHOSPHORYLATION AND STIMULUS-RESPONSE COUPLiNG......... 85 REFLECTIONS AND PROSPECTS........ 87 Receptor Phosphorylation 87 Transmembrane Signalling 88 GENERAL CONCLUSIONS 89

Phosphorylation of Proteins in Plants: Regulatory Effects and Potential Involvement in Stimulus/Response Coupling

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/0014-5793%2885%2981206-0

Identification of a calcium‐ and phospholipid‐dependent protein kinase in plant tissue

Systematic tandem-affinity-purification (TAP) of protein complexes was tremendously successful in yeast and has changed the general concept of how we understand protein function in eukaryotic cells. The transfer of this method to other model organisms has been difficult and may require specific adaptations. We were especially interested to establish a cell-type-specific TAP system for Caenorhabditis elegans, a model animal well suited to high-throughput analysis, proteomics and systems biology. By combining the high-affinity interaction between in vivo biotinylated target-proteins and streptavidin with the usage of a newly identified epitope of the publicly shared SB1 monoclonal antibody we created a novel in vivo fluorescent tag, the SnAvi-Tag. We show the versatile application of the SnAvi-Tag in Escherichia coli, vertebrate cells and in C. elegans for tandem affinity purification of protein complexes, western blotting and also for the in vivo sub-cellular localization of labelled proteins.

Angelika Schäfer

Papers

Identification of a calcium‐ and phospholipid‐dependent protein kinase in plant tissue

SnAvi – a new tandem tag for high-affinity protein-complex purification