title: Local modulation of chemoattractant concentrations by single cells: dissection using a bulk-surface computational model.
abstract: Chemoattractant gradients are usually considered in terms of sources and sinks that are independent of the chemotactic cell. However, recent interest has focused on 'self-generated' gradients, in which cell populations create their own local gradients as they move. Here, we consider the interplay between chemoattractants and single cells. To achieve this, we extend a recently developed computational model to incorporate breakdown of extracellular attractants by membrane-bound enzymes. Model equations are parametrized, using the published estimates fromDictyosteliumcells chemotaxing towards cyclic AMP. We find that individual cells can substantially modulate their local attractant field under physiologically appropriate conditions of attractant and enzymes. This means the attractant concentration perceived by receptors can be a small fraction of the ambient concentration. This allows efficient chemotaxis in chemoattractant concentrations that would be saturating without local breakdown. Similar interactions in which cells locally mould a stimulus could function in many types of directed cell motility, including haptotaxis, durotaxis and even electrotaxis.
authors.affiliation: Department of Mathematics and Statistics , University of Strathclyde , Glasgow G1 1XH , UK.
authors.forename: J A
authors.identifier: 0000-0003-4412-7057
authors.initials: JA
authors.lastname: Mackenzie
authors.affiliation: Department of Mathematics and Statistics , University of Strathclyde , Glasgow G1 1XH , UK.
authors.forename: M
authors.initials: M
authors.lastname: Nolan
authors.affiliation: Beatson Institute for Cancer Research , Switchback Road, Bearsden G61 1BD , UK.
authors.forename: R H
authors.identifier: 0000-0003-4898-040X
authors.initials: RH
authors.lastname: Insall
keywords: bulk-surface model; cell motility; chemotaxis; self-generated gradients; surface finite-elements