2. Academic Validation
  3. LRRC8A:C/E Heteromeric Channels Are Ubiquitous Transporters of cGAMP

LRRC8A:C/E Heteromeric Channels Are Ubiquitous Transporters of cGAMP

  • Mol Cell. 2020 Nov 19;80(4):578-591.e5. doi: 10.1016/j.molcel.2020.10.021.
Lauren J Lahey 1,  Rachel E Mardjuki 2,  Xianlan Wen 3,  Gaelen T Hess 4,  Christopher Ritchie 5,  Jacqueline A Carozza 2,  Volker Böhnert 5,  Merritt Maduke 3,  Michael C Bassik 4,  Lingyin Li 6
Affiliations

Affiliations

  • 1 Biophysics Program, Stanford University, Stanford, CA 94305, USA; Stanford ChEM-H, Stanford University, Stanford, CA 94305, USA.
  • 2 Stanford ChEM-H, Stanford University, Stanford, CA 94305, USA; Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
  • 3 Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA.
  • 4 Stanford ChEM-H, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA.
  • 5 Stanford ChEM-H, Stanford University, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University, Stanford, CA 94305, USA.
  • 6 Stanford ChEM-H, Stanford University, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University, Stanford, CA 94305, USA. Electronic address: lingyinl@stanford.edu.
PMID: 33171122 DOI: 10.1016/j.molcel.2020.10.021
Abstract

Extracellular 2'3'-cyclic-GMP-AMP (cGAMP) is an immunotransmitter exported by diseased cells and imported into host cells to activate the innate immune STING pathway. We previously identified SLC19A1 as a cGAMP importer, but its use across human cell lines is limited. Here, we identify LRRC8A heteromeric channels, better known as volume-regulated anion channels (VRAC), as widely expressed cGAMP transporters. LRRC8A forms complexes with LRRC8C and/or LRRC8E, depending on their expression levels, to transport cGAMP and other 2'3'-cyclic dinucleotides. In contrast, LRRC8D inhibits cGAMP transport. We demonstrate that cGAMP is effluxed or influxed via LRRC8 channels, as dictated by the cGAMP electrochemical gradient. Activation of LRRC8A channels, which can occur under diverse stresses, strongly potentiates cGAMP transport. We identify activator sphingosine 1-phosphate and inhibitor DCPIB as chemical tools to manipulate channel-mediated cGAMP transport. Finally, LRRC8A channels are key cGAMP transporters in resting primary human vasculature cells and universal human cGAMP transporters when activated.

Keywords

2’3’-cGAMP; LRRC8A; LRRC8C; LRRC8D; STING; VRAC; cGAMP; cyclic dinucleotide; transporter; vasculature.

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