期刊
PLANT CELL
卷 28, 期 7, 页码 1738-1751出版社
AMER SOC PLANT BIOLOGISTS
DOI: 10.1105/tpc.15.00870
关键词
-
资金
- Natural Sciences and Engineering Research Council (NSERC)
- Ontario government
- NSERC Discovery Grant [2014-04114]
- CIHR grant [MOP-13552]
- Canada Foundation for Innovation (CFI)
- Texas State University
- National Science Foundation [IOS-1553613]
Ca2+ signaling is critical to plant immunity; however, the channels involved are poorly characterized. Cyclic nucleotide-gated channels (CNGCs) are nonspecific, Ca2+-permeable cation channels. Plant CNGCs are hypothesized to be negatively regulated by the Ca2+ sensor calmodulin (CaM), and previous work has focused on a C-terminal CaM-binding domain (CaMBD) overlapping with the cyclic nucleotide binding domain of plant CNGCs. However, we show that the Arabidopsis thaliana isoform CNGC12 possesses multiple CaMBDs at cytosolic N and C termini, which is reminiscent of animal CNGCs and unlike any plant channel studied to date. Biophysical characterizations of these sites suggest that apoCaM interacts with a conserved isoleucine-glutamine (IQ) motif in the C terminus of the channel, while Ca2+/CaM binds additional N- and C-terminal motifs with different affinities. Expression of CNGC12 with a nonfunctional N-terminal CaMBD constitutively induced programmed cell death, providing in planta evidence of allosteric CNGC regulation by CaM. Furthermore, we determined that CaM binding to the IQ motif was required for channel function, indicating that CaM can both positively and negatively regulate CNGC12. These data indicate a complex mode of plant CNGC regulation by CaM, in contrast to the previously proposed competitive ligand model, and suggest exciting parallels between plant and animal channels.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据