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Differential association of postsynaptic signaling protein complexes in striatum and hippocampus
Author(s) -
Baucum Anthony J.,
Brown Abigail M.,
Colbran Roger J.
Publication year - 2013
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.12101
Subject(s) - striatum , hippocampus , hippocampal formation , neuroscience , excitatory postsynaptic potential , synaptic plasticity , postsynaptic density , postsynaptic potential , biology , neurotransmission , chemistry , glutamate receptor , microbiology and biotechnology , biochemistry , receptor , dopamine , inhibitory postsynaptic potential
Abstract Distinct physiological stimuli are required for bidirectional synaptic plasticity in striatum and hippocampus, but differences in the underlying signaling mechanisms are poorly understood. We have begun to compare levels and interactions of key excitatory synaptic proteins in whole extracts and subcellular fractions isolated from micro‐dissected striatum and hippocampus. Levels of multiple glutamate receptor subunits, calcium/calmodulin‐dependent protein kinase II (Ca MKII ), a highly abundant serine/threonine kinase, and spinophilin, a F‐actin and protein phosphatase 1 ( PP 1) binding protein, were significantly lower in striatal extracts, as well as in synaptic and/or extrasynaptic fractions, compared with similar hippocampal extracts/fractions. However, Ca MKII interactions with spinophilin were more robust in striatum compared with hippocampus, and this enhanced association was restricted to the extrasynaptic fraction. NMDAR GluN2B subunits associate with both spinophilin and Ca MKII , but spinophilin‐GluN2B complexes were enriched in extrasynaptic fractions whereas Ca MKII ‐GluN2B complexes were enriched in synaptic fractions. Notably, the association of GluN2B with both Ca MKII and spinophilin was more robust in striatal extrasynaptic fractions compared with hippocampal extrasynaptic fractions. Selective differences in the assembly of synaptic and extrasynaptic signaling complexes may contribute to differential physiological regulation of excitatory transmission in striatum and hippocampus.