Dynamic Interactions of Plant CNGC Subunits and Calmodulins Drive Oscillatory Ca2+ Channel Activities
| Autor: | Sheng Luan, Sisi Zhang, Qifei Gao, Legong Li, Xuyang Chai, Yajun Pan, Liming Zhou |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Molecular switch
0303 health sciences education.field_of_study Calcium channel HEK 293 cells chemistry.chemical_element Cell Biology Calcium Biology Heterotetramer General Biochemistry Genetics and Molecular Biology Molecular machine 03 medical and health sciences 0302 clinical medicine chemistry Calmodulin 2 Biophysics Pollen tube education Molecular Biology 030217 neurology & neurosurgery 030304 developmental biology Developmental Biology |
| Zdroj: | Developmental Cell. 48:710-725.e5 |
| ISSN: | 1534-5807 |
| DOI: | 10.1016/j.devcel.2018.12.025 |
| Popis: | Summary Calcium is a universal signal in all eukaryotes, but the mechanism for encoding calcium signatures remains largely unknown. Calcium oscillations control pollen tube growth and fertilization in flowering plants, serving as a model for dissecting the molecular machines that mediate calcium fluctuations. We report that pollen-tube-specific cyclic nucleotide-gated channels (CNGC18, CNGC8, and CNGC7) together with calmodulin 2 (CaM2) constitute a molecular switch that either opens or closes the calcium channel depending on cellular calcium levels. Under low calcium, calcium-free calmodulin 2 (Apo-CaM2) interacts with CNGC18-CNGC8 complex, leading to activation of the influx channel and consequently increasing cytosolic calcium levels. Calcium-bound CaM2 dissociates from CNGC18/8 heterotetramer, closing the channel and initiating a downturn of cellular calcium levels. We further reconstituted the calcium oscillator in HEK293 cells, supporting the model that Ca2+-CaM-dependent regulation of CNGC channel activity provides an auto-regulatory feedback mechanism for calcium oscillations during pollen tube growth. |
| Databáze: | OpenAIRE |
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