How far can a juxtacrine signal travel?


AUTHORS:

Markus R. Owen (1), Jonathan A. Sherratt (2) & Simon R. Myers (3)

1: Department of Mathematics, University of Utah, Salt Lake City, Utah 84112, USA.

2: Department of Mathematics, Heriot-Watt University, Edinburgh EH14 4AS, UK.

3: Academic Department of Dermatology, The Royal London Hospital, 2 Newark Street, London E1 2AT, UK.


ABSTRACT:

Juxtacrine signalling is the process of cell communication in which ligand and receptors are both anchored in the cell membrane. We develop three mathematical models for this process, involving different mathematical representations of the dynamics of membrane-bound ligand and free and bound receptors, within an epithelial sheet. We consider the dynamics of this system following a localised disturbance, such as would be provided by a source of ligand or by the generation of a free edge via wounding. We study the ability of the juxtacrine mechanism to transmit a signal away from this disturbance, and show analytically that the signal half-life can in fact be arbitrarily large. This result is quite general, since we use a generic reaction kinetic scheme; the key assumption is that ligand and receptor production are both upregulated by binding. Moreover, the result applies to all three of our model formulations. We conclude by discussing applications of the result to the particular case of the transforming growth factor alpha binding to epidermal growth factor receptor in epidermal wound healing.


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