Cell Communications among Microorganisms, Plants, and Animals: Origin, Evolution and Interplays

Cells communicate with other cells not only within the same individual but also with cells in other individuals belonging to the same species or other species. These communications occur between two unicellular species or two multicellular species, or between unicellular and multicellular species. The molecular mechanisms involved exhibit diversity and specificity but they share common basic features which allow interferences between communications in different species. Cellular communications play pivotal roles in all uni- and multi-cellular species, leading to an outstanding variety of essential biological processes not only within each species but also for numerous favorable interactions between uni- and multi-cellular species. These interactions have been made possible by the high degree of conservation of the basic mechanisms of many ligand-receptor pairs in evolutionary remote species. Moreover these inter-species communications have played an important role during Evolution and must have been positively selected, particularly when mutually beneficial. Synchronization, by chemical communications, of populations of protocells emerging from a syncitial root could have facilitated their emergence into living cell populations and explain their resemblance among microorganisms, plants and animals.