Identification of LRRC8 heteromers as an essential component of the volume-regulated anion channel VRAC.
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.
Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin.
Felizia K
FK
Voss
Florian
F
Ullrich
Jonas
J
Münch
Katina
K
Lazarow
Darius
D
Lutter
Nancy
N
Mah
Miguel A
MA
Andrade-Navarro
Jens P
JP
von Kries
Tobias
T
Stauber
Thomas J
TJ
Jentsch
D000361:Agammaglobulinemia / Q000235:genetics; D048429:Cell Size; D018118:Chloride Channels / Q000378:metabolism*; D055786:Gene Knockout Techniques; D055106:Genome-Wide Association Study; D045325:HCT116 Cells; D057809:HEK293 Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D055503:Protein Multimerization; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D013654:Taurine / Q000378:metabolism; D014162:Transfection
D018118:Chloride Channels; C485976:LRRC8A protein, human; D008565:Membrane Proteins; D034741:RNA, Small Interfering; D013654:Taurine