Calcium ions are the most ubiquitous and versatile signaling molecules in 
eukaryotic cells. Calcium homeostasis and signaling systems are crucial for both 
the normal growth of the budding yeast Saccharomyces cerevisiae and the 
intricate working of the mammalian heart. In this paper, we make a detailed 
comparison between the calcium homeostasis/signaling networks in yeast cells and 
those in mammalian cardiac myocytes. This comparison covers not only the 
components, structure and function of the networks but also includes existing 
knowledge on the measured and simulated network dynamics using mathematical 
models. Surprisingly, most of the factors known in the yeast calcium 
homeostasis/signaling network are conserved and operate similarly in mammalian 
cells, including cardiac myocytes. Moreover, the budding yeast S. cerevisiae is 
a simple organism that affords powerful genetic and genomic tools. Thus, 
exploring and understanding the calcium homeostasis/signaling system in yeast 
can provide a shortcut to help understand calcium homeostasis/signaling systems 
in mammalian cardiac myocytes. In turn, this knowledge can be used to help treat 
relevant human diseases such as pathological cardiac hypertrophy and heart 
failure.