Unifying electrostatic mechanism for phosphates and sulfates in cell signaling

Prior proposals suggested the importance of electrochemistry in signal transduction and receptor-ligand activity. Electrostatic fields associated with ions and dipoles were assigned important roles. Little is known concerning the precise mode of action in cell signaling by widespread phosphorylation. According to the hypothetical framework, molecular electrostatic potential associated with phosphate anion is a key element as a link in the communication grid, possibly inducing favorable energetics in the electron transfer process. Similar involvement appears plausible for the sulfate anion. Supporting evidence for the electrostatic mechanism is presented. Representative literature on phosphorylation in the biological domain is reviewed with emphasis on cell signaling. The treatment includes phosphates from protein, lipids, and other molecules, plus the role of reactive oxygen species. Protein sulfation is also discussed.