Co-assembly of two GluR6 kainate receptor splice variants within a functional protein complex.
Kainate receptors (KAR) are composed of several distinct subunits and splice variants, but the functional relevance of this diversity remains largely unclear. Here we show that two splice variants of the GluR6 subunit, GluR6a and GluR6b, which differ in their C-terminal domains, do not show distinct functional properties, but coassemble as heteromers in vitro and in vivo. Using a proteomic approach combining affinity purification and MALDI-TOF mass spectrometry, we found that GluR6a and GluR6b interact with two distinct subsets of cytosolic proteins mainly involved in Ca(2+) regulation of channel function and intracellular trafficking. Guided by these results, we provide evidence that the regulation of native KAR function by NMDA receptors depends on the heteromerization of GluR6a and GluR6b and interaction of calcineurin with GluR6b. Thus, GluR6a and GluR6b bring in close proximity two separate subsets of interacting proteins that contribute to the fine regulation of KAR trafficking and function.
Coussen
Françoise
F
Laboratoire "Physiologie Cellulaire de la Synapse", CNRS, UMR 5091, Institut François Magendie, Université Bordeaux, 2, rue C. Saint-Saëns, 33077 Bordeaux Cedex, France.
Perrais
David
D
Jaskolski
Frédéric
F
Sachidhanandam
Shankar
S
Normand
Elisabeth
E
Bockaert
Joel
J
Marin
Philippe
P
Mulle
Christophe
C
D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D000831:Animals, Newborn; D019556:COS Cells; D019703:Calcineurin / Q000378:metabolism; D002478:Cells, Cultured; D002490:Central Nervous System / Q000378:metabolism*; D002522:Chlorocebus aethiops; D003600:Cytosol / Q000378:metabolism; D006801:Humans; D007473:Ion Channels / Q000378:metabolism; D046911:Macromolecular Substances; D013058:Mass Spectrometry; D051379:Mice; D018345:Mice, Knockout; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D018092:Kainic Acid Receptors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism*; D000097806:GluK2 Kainate Receptor
D019703:Calcineurin; D007473:Ion Channels; D046911:Macromolecular Substances; D020033:Protein Isoforms; D018092:Kainic Acid Receptors; D000097806:GluK2 Kainate Receptor