New Twists in CDPK Regulation: dual-specificity kinases and a role for calmodulin

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

Plant calcium-dependent protein kinases (CPKs or CDPKs) are a large family of plant protein kinases that act as calcium sensors to regulate a range of processes involved in regulation of growth, stomatal aperture, hormone signaling, and immune/stress signaling. Hence, a solid understanding of the mechanisms that regulate these protein kinases is of fundamental importance. The aim of this project is to further elucidate two recently discovered novel properties of CDPKs, tyrosine autophosphorylation and calmodulin (CaM)-binding, to better understand how these factors regulate CDPK activity and plant function. The overall goals of the project are to understand how posttranslational modifications of specific CDPKs modulates their function, and to define the role these modifications play in regulating plant growth, development and responses to environmental stimuli. The approach will involve generating and measuring the activities of phosphosite CDPK mutants, determining their effect on CaM-binding, and using the directed mutants to complement CDPK null mutants to determine their effect on plant phenotype. The project will center around two broad objectives to characterize the occurrence and regulatory role of: 1) autophosphorylation of CDPKs on Ser, Thr and Tyr residues, and 2) CaM binding to CDPKs. Studies will involve recombinant proteins (and site-directed mutants) in vitro that will guide transgenic approaches to examine function in planta. The results of the proposed studies may fundamentally alter two paradigms of CDPK regulation. In addition to providing traditional student training, the project will also include summer programs that provide opportunities for recruiting underrepresented groups and involve students in lab activities. In addition, the new Professional Science Master's Program in Plant Biology/Biotechnology will engage students who are training for positions outside of academic research with a non-thesis research project. Finally, all biological materials derived from the project will be made available to the research community.