title: Drosophila Rae1 controls the abundance of the ubiquitin ligase Highwire in post-mitotic neurons.
abstract: The evolutionarily conserved Highwire (Hiw)/Drosophila Fsn E3 ubiquitin ligase complex is required for normal synaptic morphology during development and axonal regeneration after injury. However, little is known about the molecular mechanisms that regulate the Hiw E3 ligase complex. Using tandem affinity purification techniques, we identified Drosophila Rae1 as a previously unknown component of the Hiw/Fsn complex. Loss of Rae1 function in neurons results in morphological defects at the neuromuscular junction that are similar to those seen in hiw mutants. We found that Rae1 physically and genetically interacts with Hiw and restrains synaptic terminal growth by regulating the MAP kinase kinase kinase Wallenda. Moreover, we found that the Rae1 is both necessary and sufficient to promote Hiw protein abundance, and it does so by binding to Hiw and protecting Hiw from autophagy-mediated degradation. These results describe a previously unknown mechanism that selectively controls Hiw protein abundance during synaptic development.
authors.affiliation: Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Tian
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Vera
authors.initials: V
authors.lastname: Valakh
authors.forename: Aaron
authors.initials: A
authors.lastname: DiAntonio
authors.forename: Chunlai
authors.initials: C
authors.lastname: Wu
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001343:Autophagy / Q000235:genetics; D002453:Cell Cycle / Q000235:genetics*; D002853:Chromatography, Liquid / Q000379:methods; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics; D007814:Larva; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009469:Neuromuscular Junction / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000502:physiology*; D034521:Nuclear Matrix-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000378:metabolism / Q000502:physiology; D011485:Protein Binding / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000276:immunology; D053719:Tandem Mass Spectrometry / Q000379:methods; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; C409633:HIW protein, Drosophila; D009419:Nerve Tissue Proteins; D034521:Nuclear Matrix-Associated Proteins; D029543:Nucleocytoplasmic Transport Proteins; D012333:RNA, Messenger; C490523:Rae1 protein, Drosophila; D049452:Green Fluorescent Proteins; D044767:Ubiquitin-Protein Ligases