Proteomic analyses of nucleus laminaris identified candidate targets of the fragile X mental retardation protein.
The avian nucleus laminaris (NL) is a brainstem nucleus necessary for binaural processing, analogous in structure and function to the mammalian medial superior olive. In chickens (Gallus gallus), NL is a well-studied model system for activity-dependent neural plasticity. Its neurons have bipolar extension of dendrites, which receive segregated inputs from two ears and display rapid and compartment-specific reorganization in response to unilateral changes in auditory input. More recently, fragile X mental retardation protein (FMRP), an RNA-binding protein that regulates local protein translation, has been shown to be enriched in NL dendrites, suggesting its potential role in the structural dynamics of these dendrites. To explore the molecular role of FMRP in this nucleus, we performed proteomic analysis of NL, using micro laser capture and liquid chromatography tandem mass spectrometry. We identified 657 proteins, greatly represented in pathways involved in mitochondria, translation and metabolism, consistent with high levels of activity of NL neurons. Of these, 94 are potential FMRP targets, by comparative analysis with previously proposed FMRP targets in mammals. These proteins are enriched in pathways involved in cellular growth, cellular trafficking and transmembrane transport. Immunocytochemistry verified the dendritic localization of several proteins in NL. Furthermore, we confirmed the direct interaction of FMRP with one candidate, RhoC, by in vitro RNA binding assays. In summary, we provide a database of highly expressed proteins in NL and in particular a list of potential FMRP targets, with the goal of facilitating molecular characterization of FMRP signaling in future studies.
['Sakano|Hitomi|H|', 'Zorio|Diego A R|DAR|http://orcid.org/0000-0003-1761-7878', 'Wang|Xiaoyu|X|', 'Ting|Ying S|YS|', 'Noble|William S|WS|', 'MacCoss|Michael J|MJ|', 'Rubel|Edwin W|EW|', 'Wang|Yuan|Y|http://orcid.org/0000-0003-4347-7063']
D000818:Animals D030161:Avian Proteins D015153:Blotting, Western D001933:Brain Stem D002645:Chickens D002853:Chromatography, Liquid D003712:Dendrites D046169:Dermoscopy D004586:Electrophoresis D004926:Escherichia coli D051860:Fragile X Mental Retardation Protein D007150:Immunohistochemistry D061346:Laser Capture Microdissection D018613:Microscopy, Confocal D020543:Proteome D040901:Proteomics D011994:Recombinant Proteins D053719:Tandem Mass Spectrometry D000075024:rhoC GTP-Binding Protein
RhoC RNA binding protein RRID: AB_10615780 RRID: AB_1859928 RRID: AB_2155806 RRID: AB_2277755 RRID: AB_2620155 RRID: AB_297884 RRID: AB_309663 RRID: AB_357520 RRID: AB_776174 RRID: AB_94856 autism spectrum disorders cytoskeletal proteins dendritic plasticity gene ontology