title: A heat-activated calcium-permeable channel--Arabidopsis cyclic nucleotide-gated ion channel 6--is involved in heat shock responses.
abstract: An increased concentration of cytosolic calcium ions (Ca²⁺) is an early response by plant cells to heat shock. However, the molecular mechanism underlying the heat-induced initial Ca²⁺ response in plants is unclear. In this study, we identified and characterized a heat-activated Ca²⁺-permeable channel in the plasma membrane of Arabidopsis thaliana root protoplasts using reverse genetic analysis and the whole-cell patch-clamp technique. The results indicated that A. thaliana cyclic nucleotide-gated ion channel 6 (CNGC6) mediates heat-induced Ca²⁺ influx and facilitates expression of heat shock protein (HSP) genes and the acquisition of thermotolerance. GUS and GFP reporter assays showed that CNGC6 expression is ubiquitous in A. thaliana, and the protein is localized to the plasma membrane of cells. Furthermore, it was found that the level of cytosolic cAMP was increased by a mild heat shock, that CNGC6 was activated by cytosolic cAMP, and that exogenous cAMP promoted the expression of HSP genes. The results reveal the role of cAMP in transduction of heat shock signals in plants. The correlation of an increased level of cytosolic cAMP in a heat-shocked plant with activation of the Ca²⁺ channels and downstream expression of HSP genes sheds some light on how plants transduce a heat stimulus into a signal cascade that leads to a heat shock response.
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Han
authors.forename: Jianhai
authors.initials: J
authors.lastname: Wu
authors.forename: Shuzhi
authors.initials: S
authors.lastname: Zheng
authors.forename: Zhonglin
authors.initials: Z
authors.lastname: Shang
authors.forename: Daye
authors.initials: D
authors.lastname: Sun
authors.forename: Rengang
authors.initials: R
authors.lastname: Zhou
authors.forename: Bing
authors.initials: B
authors.lastname: Li
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism*; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000235:genetics / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D006360:Heat-Shock Proteins / Q000502:physiology; D018869:Heat-Shock Response; D016254:Mutagenesis, Insertional; D018408:Patch-Clamp Techniques; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; C588162:CNGC6 protein, Arabidopsis; D054815:Cyclic Nucleotide-Gated Cation Channels; D006360:Heat-Shock Proteins; D000242:Cyclic AMP; D002118:Calcium