A novel ubiquitin-specific protease, synUSP, is localized at the post-synaptic density and post-synaptic lipid raft.
Recent reports suggest an important role for protein ubiquitination in synaptic plasticity. We cloned, from the rat brain, a novel gene that encoded an ubiquitin-specific protease (USP), and termed this protein synaptic ubiquitin-specific protease (synUSP, GenBankTM Accession no. AB073880). The homologous human gene was mapped to a locus on chromosome 1p36.12. The deduced synUSP protein consisted of 1036 amino acids, and possessed an ubiquitin-like domain at the C-terminus, Cys- and His-boxes, leucine zipper motifs, and six amino acid-repeats of L/ILCPHG. The protein possessed de-ubiquitinating activity toward a model substrate, as expected from its sequence. The protein of 125 kDa was present in the rat brain; in particular, it was enriched in the post-synaptic density and the dendritic lipid raft fractions. The immunostaining of cortical neurons confirmed the post-synaptic localization. The mRNA for synUSP was localized to dendrites, as well as somas, of neuronal cells. Thus, both the mRNA and the protein were localized in the post-synaptic compartments. These results suggest a regulatory mechanism for the ubiquitin-related system at the post-synaptic sites.
Tian
Qing Bao
QB
Department of Neuroplasty, Research Institute on Aging and Adaptation, Shinshu University Graduate School of Medicine, Matsumoto, Japan.
Okano
Akira
A
Nakayama
Kohzo
K
Miyazawa
Shoko
S
Endo
Shogo
S
Suzuki
Tatsuo
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003712:Dendrites / Q000378:metabolism; D010450:Endopeptidases / Q000235:genetics* / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000737:chemistry / Q000378:metabolism; D013569:Synapses / Q000378:metabolism*; D064570:Ubiquitin-Specific Proteases
D012333:RNA, Messenger; D010450:Endopeptidases; D064570:Ubiquitin-Specific Proteases; C579219:Usp31 protein, rat