CALMODULIN AND PROTEINS IN PLANTS

Abstract

ABSTRACT Calmodulin is a small Ca2+-binding protein that acts to transduce second mes- senger signals into a wide array of cellular responses. Plant calmodulins share many structural and functional features with their homologs from animals and yeast, but the expression of multiple protein isoforms appears to be a distinctive feature of higher plants. Calmodulin acts by binding to short peptide sequences within target proteins, thereby inducing structural changes, which alters their ac- tivities in response to changes in intracellular Ca2+ concentration. The spectrum of plant calmodulin-binding proteins shares some overlap with that found in ani- mals, but a growing number of calmodulin-regulated proteins in plants appear to be unique. Ca2+-binding and enzymatic activation properties of calmodulin are discussed emphasizing the functional linkages between these processes and the diverse pathways that are dependent on Ca2+ signaling