The Physics of Signaling

The Science Sampler blog features a post on cellular signaling. From the opening paragraph:

"This is a very simple paper that attempts to answer a simple question – does physics play any role in regulating cell siganling. As cell biologists we generally like to think of signaling cascades as regulating cellular processes. We consider that an extracellular ligand binds a receptor triggering a cascade that results in some cellular behavior. The Odde lab however takes a different approach and proposes that physics, specifically cell size and shape play an important role in regulating cell signaling."

The issues raised by the Odde lab are far from settled and as the blog author pointed out it raised a chicken- egg scenario that is not uncommon in biology. The question raised was whether physics led to signaling or did signaling come first? They are consistent with each other but which is the actual causal factor accounting for the other?