title: Excitable behavior can explain the "ping-pong" mode of communication between cells using the same chemoattractant.
abstract: Here we elucidate a paradox: how a single chemoattractant-receptor system in two individuals is used for communication despite the seeming inevitability of self-excitation. In the filamentous fungus Neurospora crassa, genetically identical cells that produce the same chemoattractant fuse via the homing of individual cell protrusions toward each other. This is achieved via a recently described "ping-pong" pulsatile communication. Using a generic activator-inhibitor model of excitable behavior, we demonstrate that the pulse exchange can be fully understood in terms of two excitable systems locked into a stable oscillatory pattern of mutual excitation. The most puzzling properties of this communication are the sudden onset of oscillations with final amplitude, and the absence of seemingly inevitable self-excitation. We show that these properties result directly from both the excitability threshold and refractory period characteristic of excitable systems. Our model suggests possible molecular mechanisms for the ping-pong communication.
authors.affiliation: Centre for Systems Biology, University of Edinburgh, Edinburgh, UK. andrew.goryachev@ed.ac.uk
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Goryachev
authors.forename: Alexander
authors.initials: A
authors.lastname: Lichius
authors.forename: Graham D
authors.initials: GD
authors.lastname: Wright
authors.forename: Nick D
authors.initials: ND
authors.lastname: Read
mesh_terms: D002450:Cell Communication / Q000502:physiology*; D008962:Models, Theoretical; D009492:Neurospora crassa / Q000166:cytology; D015398:Signal Transduction / Q000502:physiology*