Proteomic studies of a single CNS synapse type: the parallel fiber/purkinje cell synapse.
Precise neuronal networks underlie normal brain function and require distinct classes of synaptic connections. Although it has been shown that certain individual proteins can localize to different classes of synapses, the biochemical composition of specific synapse types is not known. Here, we have used a combination of genetically engineered mice, affinity purification, and mass spectrometry to profile proteins at parallel fiber/Purkinje cell synapses. We identify approximately 60 candidate postsynaptic proteins that can be classified into 11 functional categories. Proteins involved in phospholipid metabolism and signaling, such as the protein kinase MRCKgamma, are major unrecognized components of this synapse type. We demonstrate that MRCKgamma can modulate maturation of dendritic spines in cultured cortical neurons, and that it is localized specifically to parallel fiber/Purkinje cell synapses in vivo. Our data identify a novel synapse-specific signaling pathway, and provide an approach for detailed investigations of the biochemical complexity of central nervous system synapse types.
Selimi
Fekrije
F
Laboratory of Molecular Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA.
Cristea
Ileana M
IM
Heller
Elizabeth
E
Chait
Brian T
BT
Heintz
Nathaniel
N
D000818:Animals; D049229:Dendritic Spines / Q000378:metabolism; D051379:Mice; D009412:Nerve Fibers / Q000737:chemistry* / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000302:isolation & purification / Q000502:physiology; D040901:Proteomics; D011689:Purkinje Cells / Q000737:chemistry* / Q000378:metabolism; D017470:Receptors, Glutamate / Q000096:biosynthesis / Q000302:isolation & purification; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D015398:Signal Transduction; D013569:Synapses / Q000737:chemistry* / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology
D010743:Phospholipids; D017470:Receptors, Glutamate; D011993:Recombinant Fusion Proteins; C107913:glutamate receptor delta 2; C541750:MRCKgamma protein, mouse; D017346:Protein Serine-Threonine Kinases