The vacuolar sorting receptors (VSRs) are specific to plants and are responsible for sorting and transporting particular proteins from the trans-Golgi network to the vacuole. This process is critically important for various cellular functions, including storing nutrients during seed development. Despite many years of intense studies on VSRs, a complete relation between function and structure has not yet been revealed. Here, we present the crystal structure of the entire luminal region of glycosylated VSR1 from Arabidopsis thaliana (AtVSR1) for the first time. The structure provides insights into the tertiary and quaternary structures of VSR1, which are composed of an N-terminal protease-associated (PA) domain, a unique central region, and one epidermal growth factor (EGF)-like domain followed by two disordered EGF-like domains. The structure of VSR1 exhibits unique characteristics, the significance of which is yet to be fully understood.
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http://dx.doi.org/10.1038/s41598-024-57975-2 | DOI Listing |
Autophagy
December 2024
Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
Lipophagy is a selective type of autophagy where lipid droplets are targeted to the lysosome/vacuole for degradation. Even though lipophagy has been reported in various species, many questions remain unaddressed. How are the lipid droplets sequestered to the lysosome? What is the lipophagy receptor(s)? How is this receptor(s) regulated at a posttranslational level? A new collaborative study among several universities conducted on mouse and human hepatocytes sheds light on these questions, deciphering the lipophagy mechanism in the liver.
View Article and Find Full Text PDFFront Neurosci
December 2024
Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin und Humboldt-Universität zu Berlin, Berlin, Germany.
Introduction: Cohen syndrome (CS) is an early-onset pediatric neurodevelopmental disorder characterized by postnatal microcephaly and intellectual disability. An accurate diagnosis for individuals with CS is crucial, particularly for their caretakers and future prospects. CS is predominantly caused by rare homozygous or compound heterozygous pathogenic variants in the vacuolar protein sorting-associated 13B () gene, which disrupt protein translation and lead to a loss of function (LoF) of the encoded VPS13B protein.
View Article and Find Full Text PDFDev 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 PDFBiochem Soc Trans
December 2024
Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, U.K.
Glycosphingolipids (GSLs) are vital components of the plasma membrane (PM), where they play crucial roles in cell function. GSLs form specialised membrane microdomains that organise lipids and proteins into functional platforms for cell adhesion and signalling. GSLs can also influence the function of membrane proteins and receptors, via direct protein-lipid interactions thereby affecting cell differentiation, proliferation, and apoptosis.
View Article and Find Full Text PDFAutophagy
December 2024
College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea.
SORT1 (sortilin 1), a member of the the Vps10 (vacuolar protein sorting 10) family, is involved in hepatic lipid metabolism by regulating very low-density lipoprotein (VLDL) secretion and facilitating the lysosomal degradation of CES1 (carboxylesterase 1), crucial for triglyceride (TG) breakdown in the liver. This study explores whether SORT1 is targeted for degradation by chaperone-mediated autophagy (CMA), a selective protein degradation pathway that directs proteins containing KFERQ-like motifs to lysosomes via LAMP2A (lysosomal-associated membrane protein 2A). Silencing LAMP2A or HSPA8/Hsc70 with siRNA increased cytosolic SORT1 protein levels.
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