Protein quality control (PQC) is carried out in part by the chaperone Hsp70, in concert with adapters of the J-domain protein (JDP) family. The JDPs, also called Hsp40s, are thought to recruit Hsp70 into complexes with specific client proteins. However, the molecular principles regulating this process are not well understood. We describe the design of a set of Hsp70 binding proteins that either inhibited or stimulated Hsp70's ATPase activity; a stimulating design promoted the refolding of denatured luciferase , similar to native JDPs. Targeting of this design to intracellular condensates resulted in their nearly complete dissolution. The designs inform our understanding of chaperone structure-function relationships and provide a general and modular way to target PQC systems to condensates and other cellular targets.
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http://dx.doi.org/10.1101/2023.09.18.558356 | DOI Listing |
Sci Adv
January 2025
Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
Hedgehog (Hh) morphogen governs embryonic development and tissue homeostasis through the Ci/Gli family transcription factors. Here we report that Hh induces phase separation of the fused (Fu)/Ulk family kinases to allosterically regulate Ci/Gli. We find that Hh-induced phosphorylation of Fu/Ulk3 promotes SUMOylation of their inverted phosphorylation-dependent SUMOylation motifs.
View Article and Find Full Text PDFLately, important advancements in visualizing RNAs in fixed and live cells have been achieved. While mRNA imaging techniques are well-established, the development of effective methods for studying non-coding RNAs (ncRNAs) in living cells are still challenging but necessary, as they show a variety of functions and intracellular localizations, including participation in highly dynamic processes like phase-transition, which is still poorly studied in vivo. Addressing this issue, we tagged two exemplary ncRNAs with the fluorescent RNA (fRNA) Pepper.
View Article and Find Full Text PDFFront Cell Dev Biol
December 2024
State Key Laboratory of Systems Medicine for Cancer, Shanghai Cancer Institute, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Liquid-liquid phase separation (LLPS) drives the formation of membraneless intracellular compartments within both cytoplasm and nucleus. These compartments can form distinct physicochemical environments, and in particular display different concentrations of proteins, RNA, and macromolecules compared to the surrounding cytosol. Recent studies have highlighted the significant role of aberrant LLPS in cancer development and progression, impacting many core processes such as oncogenic signalling pathways, transcriptional dysregulation, and genome instability.
View Article and Find Full Text PDFMolecules
December 2024
DNA Damage Laboratory of the Food Science Department, Faculty of Pharmacy, Medical University of Lodz, ul. Muszynskiego 1, 90-151 Lodz, Poland.
Each cell in the human body is continually exposed to harmful external and internal factors. During evolution, cells have developed various defence systems, divided into enzymatic and non-enzymatic types, to which low-weight molecule antioxidants belong. In this article, the ionisation potential and electron affinity, as well as global reactivity descriptors of Vitamin C, Melatonin, Uric Acids, and N-acetyl-L-cysteine, were theoretically investigated at the MP-2/aug-cc-pVTZ level of theory in the condensed (aqueous) phase.
View Article and Find Full Text PDFCoordination between growth and division is a fundamental feature of cells. In many syncytia, cell growth must couple with multiple nuclear divisions in one cytoplasm. In the fungus, cell-cycle progression and hyphal elongation require condensates formed by the protein Whi3 in complex with distinct mRNA species.
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