Here, we study and compare the mechanisms of action of the GroEL/GroES and the TRiC chaperonin systems on MreB client protein variants extracted from E. coli. MreB is a homologue to actin in prokaryotes. Single-molecule fluorescence correlation spectroscopy (FCS) and time-resolved fluorescence polarization anisotropy report the binding interaction of folding MreB with GroEL, GroES and TRiC. Fluorescence resonance energy transfer (FRET) measurements on MreB variants quantified molecular distance changes occurring during conformational rearrangements within folding MreB bound to chaperonins. We observed that the MreB structure is rearranged by a binding-induced expansion mechanism in TRiC, GroEL and GroES. These results are quantitatively comparable to the structural rearrangements found during the interaction of β-actin with GroEL and TRiC, indicating that the mechanism of chaperonins is conserved during evolution. The chaperonin-bound MreB is also significantly compacted after addition of AMP-PNP for both the GroEL/ES and TRiC systems. Most importantly, our results showed that GroES may act as an unfoldase by inducing a dramatic initial expansion of MreB (even more than for GroEL) implicating a role for MreB folding, allowing us to suggest a delivery mechanism for GroES to GroEL in prokaryotes.
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http://dx.doi.org/10.1038/srep28386 | DOI Listing |
Med Mol Morphol
December 2024
Project Team for Study of Nanotransportation System, Center for Medical Research and Development, Osaka Medical and Pharmaceutical University, 2-7 Daigaku-Machi, Takatsuki, Osaka, 569-8686, Japan.
Helicobacter pylori possesses an intrabacterial nanotransportation system (ibNoTS) for transporting VacA, CagA, and urease within the bacterial cytoplasm. This system is controlled by the extrabacterial environment. The transport routes of the system for VacA have not yet been studied in detail.
View Article and Find Full Text PDFUnlabelled: Understanding the mechanisms that dictate the localization of cytoskeletal filaments is crucial for elucidating cell shape regulation in prokaryotes. The actin homolog MreB plays a pivotal role in maintaining the shape of many rod-shaped bacteria such as by directing cell-wall synthesis according to local curvature cues. However, the basis of MreB's curvature-dependent localization has remained elusive.
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Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, MREB II, Room 3344, 8447 John Sharp Parkway, Bryan, TX 77807, USA.
Cancer immunotherapy has revolutionized cancer treatment by leveraging the immune system to attack tumors. However, its effectiveness is often hindered by the immunosuppressive tumor microenvironment (TME), where a complex interplay of tumor, stromal, and immune cells undermines antitumor responses and allows tumors to evade immune detection. This review explores innovative strategies to modify the TME and enhance immunotherapy outcomes, focusing on the therapeutic potential of engineered bacteria.
View Article and Find Full Text PDFBio Protoc
October 2024
Department of Biology, Indian Institute of Science Education and Research, Pune, India.
bioRxiv
October 2024
Department of Microbiology, Immunology, and Biochemistry. University of Tennessee Health Science Center. Memphis, TN, USA.
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