Calmodulin as a Ca2+-sensing subunit of Arabidopsis cyclic nucleotide-gated channel complexes.

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Details zur Publikation

Autor(en): Fischer C, DeFalco TA, Karia P, Snedden WA, Moeder W, Yoshioka K, Dietrich P
Zeitschrift: Plant & cell physiology
Jahr der Veröffentlichung: 2017
Band: 58
Heftnummer: 7
Seitenbereich: 1208-1221
ISSN: 1471-9053
Sprache: Englisch


Ca2+ serves as a universal second messenger in eukaryotic signaling pathways, and the spatial and temporal patterns of Ca2+ concentration changes are determined by feedback and feed-forward regulation of the involved transport proteins. Cyclic nucleotide-gated channels (CNGCs) are Ca2+-permeable channels that interact with the ubiquitous Ca2+ sensor calmodulin (CaM). CNGCs interact with CaMs via diverse CaM-binding sites, including an IQ-motif, which has been identified in the C-termini of CNGC20 and CNGC12. Here we present a family-wide analysis of the IQ-motif from all 20 Arabidopsis CNGC isoforms. While most of their IQ-peptides interacted with conserved CaMs in yeast, some were unable to do so, despite high sequence conservation across the family. We showed that the CaM-binding ability of the IQ-motif is highly dependent on its proximal and distal vicinity. We determined that two alanine residues positioned N-terminal to the core IQ-sequence play a significant role in CaM-binding, and identified a polymorphism at this site that promoted or inhibited CaM-binding in yeast. Through detailed biophysical analysis of the CNGC2 IQ-motif we found that this polymorphism specifically affected the Ca2+-independent interactions with the C-lobe of CaM. This same polymorphism partially suppressed the induction of programmed cell death by CNGC11/12 in planta. Our work expands the model of CNGC regulation, and posits the C-lobe of apo-CaM is permanently associated with the channel at the N-terminal part of the IQ-domain. This mode allows CaM to function as a Ca2+-sensing regulatory subunit of the channel complex, providing a mechanism by which Ca2+ signals may be fine-tuned.

FAU-Autoren / FAU-Herausgeber

Dietrich, Petra Prof. Dr.
Professur für Zellbiologie der Pflanzen
Fischer, Cornelia
Professur für Zellbiologie der Pflanzen

Autor(en) der externen Einrichtung(en)
Queen's University
University of Toronto


Fischer, C., DeFalco, T.A., Karia, P., Snedden, W.A., Moeder, W., Yoshioka, K., & Dietrich, P. (2017). Calmodulin as a Ca2+-sensing subunit of Arabidopsis cyclic nucleotide-gated channel complexes. Plant & cell physiology, 58(7), 1208-1221.

Fischer, Cornelia, et al. "Calmodulin as a Ca2+-sensing subunit of Arabidopsis cyclic nucleotide-gated channel complexes." Plant & cell physiology 58.7 (2017): 1208-1221.


Zuletzt aktualisiert 2018-30-06 um 06:10