One lyn molecule is sufficient to initiate phosphorylation of aggregated high-affinity IgE receptors.
In response to antigenic stimuli, the multisubunit immune recognition receptors become aggregated and then phosphorylated on their cytoplasmic tyrosines. For the clonotypic receptors of B and T cells and for Fc receptors such as the high-affinity receptor for IgE (FcepsilonRI), a Src family kinase initiates this phosphorylation. We ask whether aggregation of the initiating kinase itself is required for signal transduction or whether, alternatively, a single associated kinase molecule can phosphorylate the receptors in an aggregate. We formulate the alternative molecular mechanisms mathematically and compare predictions with experimental findings on FcepsilonRI-bearing cells expressing varying amounts of the transfected Src family kinase Lyn. The data are consistent with the requirement of only a single Lyn molecule per FcepsilonRI aggregate to initiate signaling and are inconsistent with a mechanism requiring more than one Lyn molecule.
Wofsy
C
C
Department of Mathematics and Statistics, University of New Mexico, Albuquerque, NM 87131, USA.
Vonakis
B M
BM
Metzger
H
H
Goldstein
B
B
D000818:Animals; D016466:CHO Cells; D002999:Clone Cells / Q000276:immunology; D006224:Cricetinae; D018448:Models, Immunological; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D011487:Protein Conformation; D017455:Receptors, IgE / Q000276:immunology*; D014162:Transfection; D019061:src-Family Kinases / Q000276:immunology*
D017455:Receptors, IgE; D019000:Phosphotyrosine; D019061:src-Family Kinases