Regulation of cell volume is critical for many cellular and organismal functions, yet the molecular identity of a key player, the volume-regulated anion channel VRAC, has remained unknown. A genome-wide small interfering RNA screen in mammalian cells identified LRRC8A as a VRAC component. LRRC8A formed heteromers with other LRRC8 multispan membrane proteins. Genomic disruption of LRRC8A ablated VRAC currents. Cells with disruption of all five LRRC8 genes required LRRC8A cotransfection with other LRRC8 isoforms to reconstitute VRAC currents. The isoform combination determined VRAC inactivation kinetics. Taurine flux and regulatory volume decrease also depended on LRRC8 proteins. Our work shows that VRAC defines a class of anion channels, suggests that VRAC is identical to the volume-sensitive organic osmolyte/anion channel VSOAC, and explains the heterogeneity of native VRAC currents.
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http://dx.doi.org/10.1126/science.1252826 | DOI Listing |
J Physiol
December 2024
Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, IL, USA.
Volume-regulated anion channels (VRACs) are heteromeric complexes formed by proteins of the leucine-rich repeat-containing 8 (LRRC8) family. LRRC8A (also known as SWELL1) is the core subunit required for VRAC function, and it must combine with one or more of the other paralogues (i.e.
View Article and Find Full Text PDFJ Physiol
November 2024
Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany.
Volume-regulated anion channels (VRACs) formed by leucin-rich repeat containing 8 (LRRC8) proteins play a pivotal role in regulatory volume decrease by mediating the release of chloride and organic osmolytes. Apart from the regulation of cell volume, LRRC8/VRAC function underlies numerous physiological processes in vertebrate cells including membrane potential regulation, glutamate release and apoptosis. LRRC8/VRACs are also permeable to antibiotics and anti-cancer drugs, representing therefore important therapeutic targets.
View Article and Find Full Text PDFAdv Sci (Weinh)
September 2024
Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
Cytotoxic neuronal swelling and glutamate excitotoxicity are two hallmarks of ischemic stroke. However, the underlying molecular mechanisms are not well understood. Here, it is reported that SWELL1, the essential subunit of the volume-regulated anion channel (VRAC), plays a dual role in ischemic injury by promoting neuronal swelling and glutamate excitotoxicity.
View Article and Find Full Text PDFCell Death Discov
June 2024
DiBio, Unipd, via Ugo Bassi 58/B, 35131, Padova, Italy.
Ion channels are critical in enabling ion movement into and within cells and are important targets for pharmacological interventions in different human diseases. In addition to their ion transport abilities, ion channels interact with signalling and scaffolding proteins, which affects their function, cellular positioning, and links to intracellular signalling pathways. The study of "channelosomes" within cells has the potential to uncover their involvement in human diseases, although this field of research is still emerging.
View Article and Find Full Text PDFNeuroscience
July 2024
Department of Geriatrics, Xijing Hospital of Air Force Military Medical University, Xi'an 710032, China. Electronic address:
The inflammatory response plays an indispensable role in ischemia-reperfusion injury, the most significant of which is the inflammatory response caused by microglial polarization. Anti-inflammatory therapy is also an important remedial measure after failed vascular reconstruction. Maintaining the internal homeostasis of the brain is a crucial measure for suppressing the inflammatory response.
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