Expression, purification, and in vitro characterization of kinase domain of NtGCN2 from tobacco

Investigation of the Presence of Fibrillin in Sea Cucumber (Apostichopus japonicus) Body Wall by Utilizing Targeted Proteomics and Visualization Strategies

Fibrillin is an important structural protein in connective tissues. The presence of fibrillin in sea cucumber Apostichopus japonicus is still poorly understood, which limits our understanding of the role of fibrillin in the A. japonicus microstructure. The aim of this study was to clarify the presence of fibrillin in the sea cucumber A. japonicus body wall. Herein, the presence of fibrillin in sea cucumber A. japonicus was investigated by utilizing targeted proteomics and visualization strategies. The contents of three different isoforms of fibrillin with high abundance in A. japonicus were determined to be 0.96, 2.54, and 0.15 μg/g (wet base), respectively. The amino acid sequence of fibrillin (GeneBank number: PIK56741.1) that started at position 631 and ended at position 921 was selected for cloning and expressing antigen. An anti-A. japonicus fibrillin antibody with a titer greater than 1:64 000 was successfully obtained. It was observed that the distribution of fibrillin in the A. japonicus body wall was scattered and dispersed in the form of fibril bundles at the microscale. It further observed that fibrillin was present near collagen fibrils and some entangled outside the collagen fibrils at the nanoscale. Moreover, the stoichiometry of the most dominant collagen and fibrillin molecules in A. japonicus was determined to be approximately 250:1. These results contribute to an understanding of the role of fibrillin in the sea cucumber microstructure.

Review: Emerging roles of the signaling network of the protein kinase GCN2 in the plant stress response

The pan-eukaryotic protein kinase GCN2 (General Control Nonderepressible2) regulates the translation of mRNAs in response to external and metabolic conditions. Although GCN2 and its substrate, translation initiation factor 2 (eIF2) α, and several partner proteins are substantially conserved in plants, this kinase has assumed novel functions in plants, including in innate immunity and retrograde signaling between the chloroplast and cytosol. How exactly some of the biochemical paradigms of the GCN2 system have diverged in the green plant lineage is only partially resolved. Specifically, conflicting data underscore and cast doubt on whether GCN2 regulates amino acid biosynthesis; also whether phosphorylation of eIF2α can in fact repress global translation or activate mRNA specific translation via upstream open reading frames; and whether GCN2 is controlled in vivo by the level of uncharged tRNA. This review examines the status of research on the eIF2α kinase, GCN2, its function in the response to xenobiotics, pathogens, and abiotic stress conditions, and its rather tenuous role in the translational control of mRNAs.