title: Coarsening and accelerated equilibration in mass-conserving heterogeneous nucleation.
abstract: We propose a model of mass-conserving heterogeneous nucleation to describe the dynamics of ligand-receptor binding in closed cellular compartments. When the ligand dissociation rate is small, competition among receptors for free ligands gives rise to two very different long-time ligand-receptor cluster-size distributions. Cluster sizes first plateau to a long-lived, initial-condition-dependent, "metastable" distribution, and coarsen only much later to a qualitatively different equilibrium one. Surprisingly, we also find parameters for which a very special subset of clusters have equal metastable and equilibrium sizes, appearing to equilibrate much faster than the rest. Our results provide a quantitative framework for ligand-binding kinetics and suggest a mechanism by which different clusters can approach their equilibrium sizes in unexpected ways.
authors.affiliation: Deptartments of Biomathematics and Mathematics, UCLA, Los Angeles, CA 90095-1766, USA.
authors.forename: Tom
authors.initials: T
authors.lastname: Chou
authors.forename: Maria R
authors.initials: MR
authors.lastname: D'Orsogna
mesh_terms: D000199:Actins / Q000737:chemistry; D001703:Biophysics / Q000379:methods*; D003585:Cell Biology; D007700:Kinetics; D008024:Ligands; D015233:Models, Statistical; D008962:Models, Theoretical; D011485:Protein Binding
chemical_list: D000199:Actins; D008024:Ligands