Space – the not-so-final frontier. Cellular systems, ranging from atrial tissue, to gastro-intestinal cellular walls, and salivary glands, all exploit spatial distributions of signaling mechanisms. I will present investigations of arrangements for calcium (Ca2+) transporters within varied geometric configurations for several cell types, illustrating the importance for the cellular spatial frontier. For instance, arrangements of Ca2+ release sites (ryanodine receptor in the cardiac tissue, inositol trisphosphate in other tissues) lead to either waves of Ca2+ disrupting coupled electrical control, essential depletions of endoplasmic reticulum Ca2+ reservoirs triggering pacemaking contractions, or cell-wide spatially organised induction of ion and fluid transport. These studies were all performed computationally, exploiting the precision available to mathematical and computing methods complementing experimental techniques for teasing out the subtle and important influence of space.
