Role of extracellular cations in cell motility, polarity, and chemotaxis

David R Soll¹, Deborah Wessels¹, Daniel F Lusche¹, Spencer Kuhl¹, Amanda Scherer¹, Shawna Grimm^1,2
1Monoclonal Antibody Research Institute, Developmental Studies, Hybridoma Bank, Department of Biology, University of Iowa, Iowa City; ²Mercy Medical Center, Surgical Residency Program, Des Moines, Iowa, USA

Abstract: The concentration of cations in the aqueous environment of free living organisms and cells within the human body influence motility, shape, and chemotaxis. The role of extracellular cations is usually perceived to be the source for intracellular cations in the process of homeostasis. The role of surface molecules that interact with extracellular cations is believed to be that of channels, transporters, and exchangers. However, the role of Ca²⁺ as a signal and chemoattractant and the discovery of the Ca²⁺ receptor have demonstrated that extracellular cations can function as signals at the cell surface, and the plasma membrane molecules they interact with can function as bona fide receptors that activate coupled signal transduction pathways, associated molecules in the plasma membrane, or the cytoskeleton. With this perspective in mind, we have reviewed the cationic composition of aqueous environments of free living cells and cells that move in multicellular organisms, most notably humans, the range of molecules interacting with cations at the cell surface, the concept of a cell surface cation receptor, and the roles extracellular cations and plasma membrane proteins that interact with them play in the regulation of motility, shape, and chemotaxis. Hopefully, the perspective of this review will increase awareness of the roles extracellular cations play and the possibility that many of the plasma membrane proteins that interact with them could also play roles as receptors.

Keywords: extracellular cations, chemotaxis, transporters, calcium, receptors