Howard Teresinki PhD Candidate, Snedden Lab, Queen's University Identification and characterization of novel targets for a subfamily of Arabidopsis calmodulin-like (CML) proteins
Calcium is a ubiquitous second messenger in signal transduction pathways of all eukaryotic cells. In plants, calcium signalling plays critical roles in a variety of developmental processes as well as during cellular responses to abiotic and biotic stress. The evolutionarily-conserved calcium sensor, Calmodulin (CaM), responds to calcium signals and, through protein-protein interactions in cells, facilitates downstream responses. Plants possess an additional and unique family of “calmodulin-like” (CML) calcium sensors which, in Arabidopsis thaliana, contains 50 members. Despite this expanded complexity, few of the binding partners and/or in vivo functions of CMLs are known. Here I present data from my PhD thesis demonstrating that CaM and a subfamily of biochemically unusual CMLs are capable of interacting with specialized structural domains from among three distinct and unrelated protein families in Arabidopsis. I utilised a combination of genetic, biochemical, and biophysical approaches to explore the physical properties and physiological roles of CML interactions with these putative targets. Collectively, my data suggests novel functions for plant CMLs in gene regulation and cytoskeletal activity.