Multiple roles of wheat calmodulin genes during stress treatment and TaCAM2-D as a positive regulator in response to drought and salt tolerance

Calmodulin (CaM) and calmodulin-like (CML) proteins are the most prominent calcium (Ca²⁺) sensing proteins involved in Ca²⁺-signaling processes. However, the function of these calcium sensors in wheat remains unclear. In this study, 15 TaCAMs and 113 TaCMLs were identified from the wheat reference genome. The analysis of cis-acting elements and expression patterns showed that TaCAMs might play an important role in response to abiotic and biotic stresses. TaCAM2-D gene was found to be significantly upregulated under drought and salt stresses, and thus, it was selected to further explore the biological function. Moreover, TaCAM2-D was observed to be localized in the nucleus, membrane and cytoplasm. Overexpression of TaCAM2-D in Arabidopsis conferred greater tolerance to drought and salt. The prediction analysis, the yeast two-hybrid analysis, and bimolecular fluorescence complementation assay indicated that TaCAM2-D interacted with TaMPK8, which is one of the wheat mitogen-activated protein kinases. Thus, the current study provides insights into the understanding of the TaCAM and TaCML genes in wheat.

A note of caution for using calmodulin antibodies

Calmodulin (CaM) is a ubiquitous intracellular calcium receptor that regulates a plethora of cellular functions through interactions with target proteins. In mammals, an identical Calmodulin protein is expressed by 3 independent genes (CALM1, CALM2, CALM3). Therefore, antibodies generated against either of the three products (CaM1, CaM2, CaM3) of these genes cannot be distinguished, and conclusions based on the supposedly specific CaM antibodies claiming functions of one of the 3 genes may be misleading. In this paper we present 44 articles, using such antibodies for Western blot, ELISA assay, immunohistochemistry or which are based on proteomics and the use of databases with incorrect annotations, all potentially reaching misleading conclusions. This should be taken as a note of caution for researchers working with Calmodulin antibodies and misleading databases.