Calmodulin-Regulated Proteins in Plants

Calmodulin transduces second messenger Ca²⁺ signals by binding to and altering the activities of a wide array of proteins. A growing number of these proteins have now been identified in plants. Identifying these proteins is critical to understanding how Ca²⁺-based signaling is regulated, because they are not an identical set of proteins in all organisms. The following Table identifies the known or putative plant calmodulin-binding proteins and briefly describes the methods used to identify them.

One group of CaM-BPs proteins our lab is particularly interested in is the cyclic nucleotide gated channel (CNGC) family of cation channels. Details about this gene family in Arabidopsis are shown in this Table. In collaboration with Gerry Berkowitz at the University of Connecticut, we have demonstrated that plant CaM negatively regulates ion currents through Arabidopsis CNGC2 and have identified several residues in AtCNGC2 that are important determinants for high affinity CaM-binding. We are working to decouple cyclic nucleotide and Ca²⁺/CaM regulation of CNGCs in order to better understand their physiological roles by identifying mutants in AtCNGC2 in which CaM binding affinity is increased or decreased. Using these regulatory mutants, we will complement lines of Arabidopsis in which specific a CNGC family member’s function is knocked out by T-DNA-mediated insertional mutagenesis to learn more about the physiological roles of CNGCs and CaM regulation.

This page was constructed by Ray Zielinski and last updated on 12 May 2003