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1. Cell death signaling in Anopheles gambiae initiated by Bacillus thuringiensis Cry4B toxin involves Na + /K + ATPase

   https://doi.org/10.1177/15353702231188072  

   Liu, Li ; Bulla, Jr, Lee A. ( August 2023 , Experimental Biology and Medicine)

   Identifying the mechanisms by which bacterial pathogens kill host cells is fundamental to understanding how to control and prevent human and animal disease. In the case of Bacillus thuringiensis (Bt), such knowledge is critical to using the bacterium to kill insect vectors that transmit human and animal disease. For the Cry4B toxin produced by Bt, its capacity to kill Anopheles gambiae, the primary mosquito vector of malaria, is the consequence of a variety of signaling activities. We show here that Cry4B, acting as first messenger, binds specifically to the bitopic cadherin BT-R₃G-protein-coupled receptor (GPCR) localized in the midgut of A. gambiae, activating the downstream second messenger cyclic adenosine monophosphate (cAMP). The direct result of the Cry4B–BT-R₃binding is the release of α_sfrom the heterotrimeric αβγ-G-protein complex and its activation of adenylyl cyclase (AC). The upshot is an increased level of cAMP, which activates protein kinase A (PKA). The functional impact of cAMP–PKA signaling is the stimulation of Na⁺/K⁺-ATPase (NKA) which serves as an Na⁺/K⁺pump to maintain proper gradients of extracellular Na⁺and intracellular K⁺. Increased level of cAMP amplifies NKA and upsets normal ion concentration gradients. NKA, as a scaffolding protein, accelerates the first messenger signal to the nucleus, generating additional BT-R₃molecules and promoting their exocytotic trafficking to the cell membrane. Accumulation of BT-R₃on the cell surface facilitates recruitment of additional toxin molecules which, in turn, amplify the original signal in a cascade-like manner. This report provides the first evidence of a bacterial toxin using NKA via AC/PKA signaling to execute cell death.

    

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2. Arginine substitution of a cysteine in transmembrane helix M8 converts Na + ,K + -ATPase to an electroneutral pump similar to H + ,K + -ATPase

   https://doi.org/10.1073/pnas.1617951114  

   Holm, Rikke ; Khandelwal, Jaanki ; Einholm, Anja P. ; Andersen, Jens P. ; Artigas, Pablo ; Vilsen, Bente ( January 2017 , Proceedings of the National Academy of Sciences)
3. Ca 2+ entry at the plasma membrane and uptake by acidic stores is regulated by the activity of the V‐H + ‐ATPase in Toxoplasma gondii

   https://doi.org/10.1111/mmi.14722  

   Stasic, Andrew J. ; Dykes, Eric J. ; Cordeiro, Ciro D. ; Vella, Stephen A. ; Fazli, Mojtaba S. ; Quinn, Shannon ; Docampo, Roberto ; Moreno, Silvia N. J. ( April 2021 , Molecular Microbiology)

   Ca²⁺is a universal intracellular signal that regulates many cellular functions. InToxoplasma gondii, the controlled influx of extracellular and intracellular Ca²⁺into the cytosol initiates a signaling cascade that promotes pathogenic processes like tissue destruction and dissemination. In this work, we studied the role of proton transport in cytosolic Ca²⁺homeostasis and the initiation of Ca²⁺signaling. We used aT. gondiimutant of the V‐H⁺‐ATPase, a pump previously shown to transport protons to the extracellular medium, and to control intracellular pH and membrane potential and we show that proton gradients are important for maintaining resting cytosolic Ca²⁺at physiological levels and for Ca²⁺influx. Proton transport was also important for Ca²⁺storage by acidic stores and, unexpectedly, the endoplasmic reticulum. Proton transport impacted the amount of polyphosphate (polyP), a phosphate polymer that binds Ca²⁺and concentrates in acidocalcisomes. This was supported by the co‐localization of the vacuolar transporter chaperone 4 (VTC4), the catalytic subunit of the VTC complex that synthesizes polyP, with the V‐ATPase in acidocalcisomes. Our work shows that proton transport regulates plasma membrane Ca²⁺transport and control acidocalcisome polyP and Ca²⁺content, impacting Ca²⁺signaling and downstream stimulation of motility and egress inT. gondii.

    

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4. In vivo cross-linking supports a head-to-tail mechanism for regulation of the plant plasma membrane P-type H + -ATPase

   https://doi.org/10.1074/jbc.RA118.003528  

   Nguyen, Thao T. ; Sabat, Grzegorz ; Sussman, Michael R. ( November 2018 , Journal of Biological Chemistry)
5. Direct measurement of the 19 F( p , αγ ) 16 O reaction in JUNA

   https://doi.org/10.1051/epjconf/202226008004  

   Zhang, L.Y. ; Su, J. ; He, J.J. ; Wiescher, M. ; deBoer, R.J. ; Kahl, D. ; Chen, Y.J. ; Li, X.Y. ; Wang, J.G. ; Zhang, L. ; et al ( January 2022 , EPJ Web of Conferences)

   Liu, W. ; Wang, Y. ; Guo, B. ; Tang, X. ; Zeng, S. (Ed.)

   The 19 F( p , αγ ) 16 O reaction is of crucial importance for Galactic 19 F abundances and CNO cycle loss in first generation Population III stars. Due to its extremely small cross sections, the 19 F( p , αγ ) 16 O reaction has not been measured in the low energy part of the Gamow window(70-200 keV). As a day-one campaign, the experiment was performed under the extremely low cosmicray-induced background environment of the China JinPing Underground Laboratory(CJPL), one of the deepest underground laboratories in the world. The γ -ray yields were measured over E c . m . =72.4–344 keV, covering the full Gamow window for the first time. The direct experimental data will help people to expound the fluorine over-abundances, energy generation, as well as heavy-element nuclosynthesis scenario in asymptotic giant branch (AGB) stars, with the astrophysical model on the firm ground. 

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