title: A large number of receptors may reduce cellular response time variation.
abstract: Cells often have tens of thousands of receptors, even though only a few activated receptors can trigger full cellular responses. Reasons for the overabundance of receptors remain unclear. We suggest that, under certain conditions, the large number of receptors can result in a competition among receptors to be the first to activate the cell. The competition decreases the variability of the time to cellular activation, and hence results in a more synchronous activation of cells. We argue that, in simple models, this variability reduction does not necessarily interfere with the receptor specificity to ligands achieved by the kinetic proofreading mechanism. Thus cells can be activated accurately in time and specifically to certain signals. We predict the minimum number of receptors needed to reduce the coefficient of variation for the time to activation following binding of a specific ligand. Furthermore, we predict the maximum number of receptors so that the kinetic proofreading mechanism still can improve the specificity of the activation. These predictions fall in line with experimentally reported receptor numbers for multiple systems.
authors.affiliation: Department of Physics, Emory University, Atlanta, GA 30322, USA. xiang.cheng@emory.edu
authors.forename: Xiang
authors.initials: X
authors.lastname: Cheng
authors.forename: Lina
authors.initials: L
authors.lastname: Merchan
authors.forename: Martin
authors.initials: M
authors.lastname: Tchernookov
authors.forename: Ilya
authors.initials: I
authors.lastname: Nemenman
mesh_terms: D000818:Animals; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008954:Models, Biological; D011485:Protein Binding; D011487:Protein Conformation; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D008024:Ligands; D011956:Receptors, Cell Surface