from Ranjan Tamuli, Ravi Kumar, Dhruv Aditya Srivastava and Rekha Deka writing in Neurospora: Genomics and Molecular Biology:
The filamentous fungus Neurospora crassa possesses a complex Ca2+- signaling system consisting of 48 Ca2+-signaling proteins. Ca2+ is stored in several intracellular stores such as vacuoles, plasma membrane vesicles, microsomes, and mitochondria; however, second messenger systems responsible for Ca2+-release from internal stores have not been identified in N. crassa or any other filamentous fungi. The cytosolic free Ca2+ ([Ca2+]c) can be measured in living N. crassa by using Ca2+-sensitive devices such as microelectrodes, fluorescent probes, or aequorin which is a photoprotein isolated from the jellyfish Aeqorea victoria. In N. crassa, the [Ca2+]c is ~100 nM that -is effectively regulated by the Ca2+ signaling machinery -as high concentrations of Ca2+ are toxic, and minute change of [Ca2+]c may trigger several cell processes. In N. crassa, Ca2+ signaling is known to be involved in regulating several processes such as Ca2+ stress tolerance, circadian clocks, growth, ion transport, sexual development, and UV survival. The Ca2+-signaling genes and proteins in N. crassa have several characteristic sequence features. Analysis of Ca2+-signaling in mutants and the availability of the genome sequence has provided deep insight into the functions for some Ca2+-signaling genes in N. crassa.
Further reading: Neurospora: Genomics and Molecular Biology