title: Fbxo45 forms a novel ubiquitin ligase complex and is required for neuronal development.
abstract: Fbxo45 is an F-box protein that is restricted to the nervous system. Unlike other F-box proteins, Fbxo45 was found not to form an SCF complex as a result of an amino acid substitution in the consensus sequence for Cul1 binding. Proteomics analysis revealed that Fbxo45 specifically associates with PAM (protein associated with Myc), a RING finger-type ubiquitin ligase. Mice deficient in Fbxo45 were generated and found to die soon after birth as a result of respiratory distress. Fbxo45(-)(/)(-) embryos show abnormal innervation of the diaphragm, impaired synapse formation at neuromuscular junctions, and aberrant development of axon fiber tracts in the brain. Similar defects are also observed in mice lacking Phr1 (mouse ortholog of PAM), suggesting that Fbxo45 and Phr1 function in the same pathway. In addition, neuronal migration was impaired in Fbxo45(-)(/)(-) mice. These results suggest that Fbxo45 forms a novel Fbxo45-PAM ubiquitin ligase complex that plays an important role in neural development.
authors.affiliation: Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Saiga
authors.forename: Takaichi
authors.initials: T
authors.lastname: Fukuda
authors.forename: Masaki
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Hirobumi
authors.initials: H
authors.lastname: Tada
authors.forename: Hirotaka James
authors.initials: HJ
authors.lastname: Okano
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Okano
authors.forename: Keiichi I
authors.initials: KI
authors.lastname: Nakayama
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019521:Body Patterning; D001921:Brain / Q000033:anatomy & histology / Q000196:embryology / Q000378:metabolism; D002352:Carrier Proteins; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D005838:Genotype; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000378:metabolism; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D055495:Neurogenesis; D009469:Neuromuscular Junction / Q000502:physiology / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D013116:Spinal Cord / Q000033:anatomy & histology / Q000196:embryology / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D044783:F-Box Proteins; C542381:Fbxo45 protein, mouse; D046912:Multiprotein Complexes; C532954:Mycbp2 protein, mouse; D044767:Ubiquitin-Protein Ligases