Visual arrestin (Arr1) terminates rhodopsin signaling by blocking its interaction with transducin. To do this, Arr1 translocates from the inner to the outer segment of photoreceptors upon light stimulation. Mounting evidence indicates that inositol phosphates (InsPs) affect Arr1 activity, but the Arr1-InsP molecular interaction remains poorly defined. We report the structure of bovine Arr1 in a ligand-free state featuring a near-complete model of the previously unresolved C-tail, which plays a crucial role in regulating Arr1 activity. InsPs bind to the N-domain basic patch thus displacing the C-tail, suggesting that they prime Arr1 for interaction with rhodopsin and help direct Arr1 translocation. These structures exhibit intact polar cores, suggesting that C-tail removal by InsP binding is insufficient to activate Arr1. These results show how Arr1 activity can be controlled by endogenous InsPs in molecular detail.
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http://dx.doi.org/10.1016/j.str.2021.10.002 | DOI Listing |
Dev Cell
November 2024
College of Life Sciences, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China. Electronic address:
How do growth hormones interact to specify female-germline cell types in flowering plants and control production of the first female-germline cell? Here, we find that gibberellin (GA) biosynthesis and signaling are restricted in ovule primordia, with overexpression of receptors and biosynthetic enzymes resulting in multiple and enlarged megaspore mother cells (MMCs) in Arabidopsis. GA signaling machinery interacts with and promotes the degradation of cytokinin (CK) type-B Arabidopsis response regulators (ARR1/10/12), which also directly interact with DELLA proteins. CK biosynthesis and signaling components are expressed in both MMCs and sporophytic cells, with signaling negatively controlled by GA in ovule primordia, and perturbations leading to the induction of multiple, enlarged MMC-like cells.
View Article and Find Full Text PDFPlant J
November 2024
College of Horticulture, Shanxi Agricultural University, Taigu, 030801, P. R. China.
Life (Basel)
July 2024
Department of Biology, College of Sciences, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia.
The objective of this investigation is to ascertain the distinctive profile of the rhizospheric soil resistome within the Mecca region, while also evaluating the potential risks associated with the horizontal transfer of resistome determinants to the open environment and human clinical isolates. We have made metagenomic whole-genome shotgun sequencing for rhizospheric microbiomes of two endemic plants, namely and . The rhizospheric resistomes of the two plants and the abundance of antibiotic resistance genes (ARGs) were identified by cross-referencing encoded proteins with the comprehensive antibiotic resistance database (CARD).
View Article and Find Full Text PDFPLoS One
June 2024
Department of Pharmacology, Center for Molecular Neuroscience and Vision Research Center, Vanderbilt University, Nashville, TN, United States of America.
Activated GPCRs are phosphorylated and internalized mostly via clathrin-mediated endocytosis (CME), which are then sorted for recycling or degradation. We investigated how differential activation of the same GPCR affects its endocytic trafficking in vivo using rhodopsin as a model in pupal photoreceptors of flies expressing mCherry-tagged rhodopsin 1 (Rh1-mC) or GFP-tagged arrestin 1 (Arr1-GFP). Upon blue light stimulation, activated Rh1 recruited Arr1-GFP to the rhabdomere, which became co-internalized and accumulated in cytoplasmic vesicles of photoreceptors.
View Article and Find Full Text PDFPlant Cell
September 2024
Department of Bioenergy Science and Technology, Chonnam National University, Gwangju 61186, Korea.
Cytokinins regulate plant growth, development, and responses to environmental stresses such as cold via phosphorelay from cytokinin receptors to the ARABIDOPSIS RESPONSE REGULATORs (ARRs). However, the molecular mechanisms underlying the activation of type-B ARR transcriptional activity in Arabidopsis (Arabidopsis thaliana) remain unclear. Here, we show that the E3 SUMO ligase HIGH PLOIDY2 SUMOylates ARR1, a type-B ARR, at K236, triggering its activation.
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