The functions of Ca2+ in bacteria:: a role for EF-hand proteins?

In bacteria, Ca2+ is implicated in a wide variety of cellular processes, including the cell cycle and cell division. Dedicated influx and efflux systems tightly control the low cytoplasmic Ca2+ levels in prokaryotes. Additionally, the growing number of proteins containing various Ca2+-binding motifs supports the importance of Ca2+, which controls various protein functions by affecting protein stability, enzymatic activity or signal transduction. The existence of calmodulin-like proteins (containing EF-hand motifs) in bacteria is a long-standing hypothesis. Analysis of the prokaryotic protein sequences available in the databases has revealed the presence of several calmodulin-like proteins containing two or more authentic EF-hand motifs, suggesting that calmodulin-like proteins could be involved in Ca2+ regulation in bacteria.