Comparing the Calcium Binding Abilities of Two Soybean Calmodulins: Towards Understanding the Divergent Nature of Plant Calmodulins

Genome-Wide Identification and Analyses of Calmodulins and Calmodulin-like Proteins in Lotus japonicas

“…The functional redundancy of genes cannot be ruled out; however, accumulating evidence suggests that multiple CaM isoforms may have distinct and significant functions (Heo et al, 1999; Karita et al, 2004; Phean-o-pas et al, 2005; Gifford et al, 2013; Abbas et al, 2014). During the gene duplication events, there are two different kinds of homology: orthology (vertical) and paralogy (horizontal) (Das et al, 2016).…”

“…In tobacco, NtCaM13 was shown to be exclusively expressed in the root; however, 13 related CaM genes were expressed in almost all of the examined organs (Yamakawa et al, 2001). Steady state expression levels of CaM s have been reported to be modulated in different special phase of plant growth (Delk et al, 2005; Yang et al, 2014) as well as in response to external stimuli (Heo et al, 1999; Phean-o-pas et al, 2005; Gifford et al, 2013; Abbas et al, 2014). Therefore, the modulation of gene expression of a CaM isoform in specific organs allows for the possibility of functioning in a timely fashion.…”

“…Calcium (Ca 2+ ) is a universal second messenger in plant signal transduction; it acts as a mediator in many processes associated with plant growth and development as well as the physiological responses to both abiotic (light, gravity, cold, heat, touch, wounding, drought, and oxidative stress) and biotic (phytohormones, pathogens, and symbiants) factors in plants (McCormack et al, 2005; Boonburapong and Buaboocha, 2007; Gifford et al, 2013; Abbas et al, 2014). To generate specificity in response, Ca 2+ signals must be decoded by several Ca 2+ sensors or Ca 2+ -binding proteins, which usually contain a number of paired EF-hand motifs and a helix-loop-helix structure (McCormack et al, 2005; Scholz et al, 2014).…”

“…Each EF-hand motif contains two alpha helices that are connected by a 12 amino acid-residue loop (Yang and Poovaiah, 2003; Gifford et al, 2013). As is similar to what has been identified in animals, in which a single isoform of CaM is encoded by three separate genes (Fischer et al, 1988), multiple CaM genes encoding several CaM isoforms with only minor amino acid differences have been identified in several plants (McCormack and Braam, 2003; Boonburapong and Buaboocha, 2007; Gifford et al, 2013) including Arabidopsis (McCormack and Braam, 2003; Yang and Poovaiah, 2003; McCormack et al, 2005; Abbas et al, 2014), soybean (Sang et al, 1995; Heo et al, 1999; Gifford et al, 2013), pea ( Pisum sativum ; Oh and Roberts, 1990), petunia ( Petunia hybrid ; Rodriguez-Concepcion et al, 1999), rice ( Oryza sativa ; Phean-o-pas et al, 2005; Boonburapong and Buaboocha, 2007), tobacco ( Nicotiana tabacum ; Oh and Yun, 1999), and aloes leaf ( Aquilaria microcarpa ; Kurosaki and Taura, 2015). Evidence has accumulated supporting the theory that the presence of multiple diverged CaM isoforms may have distinct and significant functions, although gene redundancy cannot be ruled out as of yet.…”

“…The differential Ca 2+ sensitivity of CaMs may play an essential role in the selective target activation in different tissues in response to different stimuli by regulating CaM/target protein binding. For example, it has been shown that the expression levels of calmodulin isoforms in soybean, rice, and Arabidopsis are ubiquitous; however, they are differentially regulated by various stress signals (Heo et al, 1999; Phean-o-pas et al, 2005; Gifford et al, 2013; Abbas et al, 2014). Besides CaMs, plant tissues also have CMLs, which were found to share the same EF hand motifs with CaMs.…”