FtsZ (Filamentous temperature sensitivity Z) cell division protein from Escherichia coli binds the fluorescence probe DAPI. Bundling of FtsZ was facilitated in the presence of DAPI, and the polymers in solution remained polymerized longer time than the protofilaments formed in the absence of DAPI. DAPI decreased both the maximal velocity of the GTPase activity and the Michaelis-Menten constant for GTP, indicating that behaves like an uncompetitive inhibitor of the GTPase activity favoring the GTP form of FtsZ in the polymers. The results presented in this work support a cooperative polymerization mechanism in which the binding of DAPI favors protofilament lateral interactions and the stability of the resulting polymers.
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http://dx.doi.org/10.1016/j.abb.2007.06.032 | DOI Listing |
Mol Biol Rep
January 2025
Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
Background: Exosomes are extracellular vesicles released by cells that mediate intercellular communication and actively participate in cancer progression, metastasis, and regulation of immune response within the tumour microenvironment. Inhibiting exosome release from cancer cells could be employed as a therapeutic against cancer.
Methods And Results: In the present study, we have studied the effects of Acorus calamus in inhibiting exosome secretion via targetting Rab27a and neutral sphingomyelinase 2 (nSMase2) in HER2-positive (MDA-MB-453), hormone receptor-positive (MCF-7) and triple-negative breast cancer (MDA-MB-231) cells.
Aging Dis
January 2025
Geriatrics department, Renmin hospital of Wuhan University, Wuhan 430060, China.
Autophagy in microglia is essential for the clearance of amyloid-beta (Aβ) and amyloid plaques in Alzheimer's disease. However, reports regarding the levels of autophagy in microglia have been inconsistent; some studies indicate an early enhancement followed by a subsequent reduction, while others describe a persistently weakened state. Notably, there is a lack of systematic studies documenting the temporal changes in microglial autophagy.
View Article and Find Full Text PDFNat Commun
January 2025
Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montréal, QC, H3T 1J4, Canada.
Intense research on founding members of the RAS superfamily has defined our understanding of these critical signalling proteins, leading to the premise that small GTPases function as molecular switches dependent on differential nucleotide loading. The closest homologs of H/K/NRAS are the three-member RRAS family, and interest in the MRAS GTPase as a regulator of MAPK activity has recently intensified. We show here that MRAS does not function as a classical switch and is unable to exchange GDP-to-GTP in solution or when tethered to a lipid bilayer.
View Article and Find Full Text PDFOpen Biol
January 2025
Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus School of Medicine, Aurora, CO 80045, USA.
Protein-based nanomachines drive every cellular process. An explosion of high-resolution structures of multiprotein complexes has improved our understanding of what these machines look like and how they work, but we still know relatively little about how they assemble in living cells. For example, it has only recently been appreciated that many complexes assemble co-translationally, with at least one subunit still undergoing active translation while already interacting with other subunits.
View Article and Find Full Text PDFJ Exp Bot
January 2025
Vegetable and Fruit Improvement Center and Department of Horticultural Sciences Texas A&M University, College Station, TX 77843, USA.
Complex N-glycans are asparagine (N)-linked branched sugar chains attached to secretory proteins in eukaryotes. They are produced by modification of N-linked oligosaccharide structures in the endoplasmic reticulum (ER) and Golgi apparatus. Complex N-glycans formed in the Golgi apparatus are often assigned specific roles unique to the host organism, with their roles in plants remaining largely unknown.
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