TY - JOUR
T1 - Ca2+-regulated Ca2+ channels with an RCK gating ring control plant symbiotic associations
AU - Kim, Sunghoon
AU - Zeng, Weizhong
AU - Bernard, Shane
AU - Liao, Jun
AU - Venkateshwaran, Muthusubramanian
AU - Ane, Jean Michel
AU - Jiang, Youxing
N1 - Publisher Copyright:
© 2019, The Author(s).
PY - 2019/12/1
Y1 - 2019/12/1
N2 - A family of plant nuclear ion channels, including DMI1 (Does not Make Infections 1) and its homologs CASTOR and POLLUX, are required for the establishment of legume-microbe symbioses by generating nuclear and perinuclear Ca2+ spiking. Here we show that CASTOR from Lotus japonicus is a highly selective Ca2+ channel whose activation requires cytosolic/nucleosolic Ca2+, contrary to the previous suggestion of it being a K+ channel. Structurally, the cytosolic/nucleosolic ligand-binding soluble region of CASTOR contains two tandem RCK (Regulator of Conductance for K+) domains, and four subunits assemble into the gating ring architecture, similar to that of large conductance, Ca2+-gated K+ (BK) channels despite the lack of sequence similarity. Multiple ion binding sites are clustered at two locations within each subunit, and three of them are identified to be Ca2+ sites. Our in vitro and in vivo assays also demonstrate the importance of these gating-ring Ca2+ binding sites to the physiological function of CASTOR as well as DMI1.
AB - A family of plant nuclear ion channels, including DMI1 (Does not Make Infections 1) and its homologs CASTOR and POLLUX, are required for the establishment of legume-microbe symbioses by generating nuclear and perinuclear Ca2+ spiking. Here we show that CASTOR from Lotus japonicus is a highly selective Ca2+ channel whose activation requires cytosolic/nucleosolic Ca2+, contrary to the previous suggestion of it being a K+ channel. Structurally, the cytosolic/nucleosolic ligand-binding soluble region of CASTOR contains two tandem RCK (Regulator of Conductance for K+) domains, and four subunits assemble into the gating ring architecture, similar to that of large conductance, Ca2+-gated K+ (BK) channels despite the lack of sequence similarity. Multiple ion binding sites are clustered at two locations within each subunit, and three of them are identified to be Ca2+ sites. Our in vitro and in vivo assays also demonstrate the importance of these gating-ring Ca2+ binding sites to the physiological function of CASTOR as well as DMI1.
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U2 - 10.1038/s41467-019-11698-5
DO - 10.1038/s41467-019-11698-5
M3 - Article
C2 - 31420535
AN - SCOPUS:85070799417
SN - 2041-1723
VL - 10
JO - Nature communications
JF - Nature communications
IS - 1
M1 - 3703
ER -