Fast inactivation in voltage-gated potassium channels has traditionally been associated exclusively with the N-terminus. Here, we explore the role of the T1 domain using a series of chimeric channels. A chimeric channel, 4N/2, (N-terminus from the rapidly inactivating hKv1.4, and the channel body from the non-inactivating hKv1.2), exhibited slower and incomplete inactivation as compared to the wild-type hKv1.4. Replacing the T1 domain of 4N2 with that from hKv1.2 (4N/2T1/2), restored inactivation, while that from hKv1.1 (4N/1T1/2) completely abolished inactivation. Based on these observations, we hypothesize a correlation between the tetramerization domain and the putative inactivation domain receptor in the process of rapid inactivation of hKv1 channels.
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http://dx.doi.org/10.1016/j.bbrc.2009.08.001 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Neuroscience, Farber Institute for Neuroscience and Jefferson Synaptic Biology Center, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, PA 19107.
Use-dependent spike broadening (UDSB) results from inactivation of the voltage-gated K (Kv) channels that regulate the repolarization of the action potential. However, the specific signaling and molecular processes that modulate UDSB have remained elusive. Here, we applied an adeno-associated viral vector approach and dynamic clamping to conclusively demonstrate how multisite phosphorylation of the N-terminal inactivation domain (NTID) of the Kv3.
View Article and Find Full Text PDFElife
December 2024
Experimental Otology Group, InnerEarLab, Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany.
To encode continuous sound stimuli, the inner hair cell (IHC) ribbon synapses utilize calcium-binding proteins (CaBPs), which reduce the inactivation of their Ca1.3 calcium channels. Mutations in the gene underlie non-syndromic autosomal recessive hearing loss DFNB93.
View Article and Find Full Text PDFFront Med (Lausanne)
December 2024
Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Hannover, Germany.
Rapid and sensitive diagnostic measures are a pre-requisite for the control of SARS-CoV-2 outbreaks. Dogs detect SARS-CoV-2-infected human individuals with high speed due to their extraordinary olfactory acuity. In the post-pandemic phase of SARS-CoV-2 it is difficult to obtain samples from infected humans for scent dog training.
View Article and Find Full Text PDFJ Food Prot
December 2024
U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038-8551.
Biochar has been used to accelerate heating profiles during composting by increasing oxygenation, which could also reduce microbial pathogens. However, the antimicrobial inactivation of foodborne pathogens in compost, by amending with biochar without increased heating profiles, has not been evaluated. In this study, we examined the ability of biochar to inactivate E.
View Article and Find Full Text PDFBiochemistry
December 2024
Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States.
F-dependent glucose-6-phosphate dehydrogenase (FGD) catalyzes the conversion of glucose-6-phosphate (G6P) to 6-phosphogluconolactone, using cofactor F as the hydride transfer acceptor. Our previous pH dependence studies suggested that E109 serves as an active site acid, donating a proton to the N-1 position of F, while leaving the role of H40 unanswered, which was previously suggested to serve as the active site base. This work utilizes thermodynamic and kinetic studies to elucidate additional mechanistic details concerning the roles of H40 and E13.
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