Significance of calcium binding, tyrosine phosphorylation, and lysine trimethylation for the essential function of calmodulin in vertebrate cells analyzed in a novel gene replacement system.

Calmodulin (CaM) was shown to be essential for survival of lower eukaryotes by gene deletion experiments. So far, no CaM gene deletion was reported in higher eukaryotes. In vertebrates, CaM is expressed from several genes, which encode an identical protein, making it difficult to generate a model system to study the effect of CaM gene deletion.