Dual Function Molecules and Processes in Cell Fate Decision: A Preface to the Special Issue.

A lot of water has passed under the bridge since 1999, when C.J. Jeffery stated in a pioneering review that "the idea of one gene-one protein-one function has become too simple" [[1]], and presented to the scientific community the concept of "moonlighting proteins", indicating with this term proteins that can perform different, often unrelated, functions in the cells. As above reported, the Janus role is not restricted to molecules, but also regards cellular processes determining cell fate, such as the following: (1) signal transduction, the complex cell response to external inputs; (2) gene expression, the fine cell capability of encoding proteins or regulative RNAs; (3) autophagy, the form of intracellular material degradation that can represent a pro-survival response or culminate in cell death; (4) Cell stress response, the cell ability to respond to injury, toxicity, or oxidative stress; (5) Cell adhesion, the whole functional interactions that the cells establish with each other or with the extracellular matrix; (6) Cell transformation into cancer, the process that causes the cells to undergo uncontrolled proliferation, becoming tumor cells and acquiring malignancy. In this regard, Tsuchiya et al. elucidate the genomic mechanism that guides the cell-fate determination from embryo to cancer development [[6]]. They behave like Dr Jekyll when they protect the cells from cell stress conditions, but they can turn into Mr. Hyde when they exasperate the immune responses or promote cancer development. [Extracted from the article]