title: A Computational Model for the AMPA Receptor Phosphorylation Master Switch Regulating Cerebellar Long-Term Depression.
abstract: The expression of long-term depression (LTD) in cerebellar Purkinje cells results from the internalisation of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors (AMPARs) from the postsynaptic membrane. This process is regulated by a complex signalling pathway involving sustained protein kinase C (PKC) activation, inhibition of serine/threonine phosphatase, and an active protein tyrosine phosphatase, PTPMEG. In addition, two AMPAR-interacting proteins-glutamate receptor-interacting protein (GRIP) and protein interacting with C kinase 1 (PICK1)-regulate the availability of AMPARs for trafficking between the postsynaptic membrane and the endosome. Here we present a new computational model of these overlapping signalling pathways. The model reveals how PTPMEG cooperates with PKC to drive LTD expression by facilitating the effect of PKC on the dissociation of AMPARs from GRIP and thus their availability for trafficking. Model simulations show that LTD expression is increased by serine/threonine phosphatase inhibition, and negatively regulated by Src-family tyrosine kinase activity, which restricts the dissociation of AMPARs from GRIP under basal conditions. We use the model to expose the dynamic balance between AMPAR internalisation and reinsertion, and the phosphorylation switch responsible for the perturbation of this balance and for the rapid plasticity initiation and regulation. Our model advances the understanding of PF-PC LTD regulation and induction, and provides a validated extensible platform for more detailed studies of this fundamental synaptic process.
authors.affiliation: Department of Computer Science, University of York, York, United Kingdom.|Computational Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Gallimore
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
authors.forename: A Radu
authors.initials: AR
authors.lastname: Aricescu
authors.affiliation: Department of Physiology, Graduate School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Michisuke
authors.initials: M
authors.lastname: Yuzaki
authors.affiliation: Department of Computer Science, University of York, York, United Kingdom.
authors.forename: Radu
authors.initials: R
authors.lastname: Calinescu
mesh_terms: D002531:Cerebellum / Q000166:cytology / Q000502:physiology*; D019295:Computational Biology; D003198:Computer Simulation; D049229:Dendritic Spines; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D008959:Models, Neurological; D010766:Phosphorylation; D018091:Receptors, AMPA / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism
chemical_list: D018091:Receptors, AMPA