title: Activation-induced cytidine deaminase shuttles between nucleus and cytoplasm like apolipoprotein B mRNA editing catalytic polypeptide 1.
abstract: Activation-induced cytidine deaminase (AID) is a molecule central to initiating class switch recombination, somatic hypermutation, and gene conversion of Ig genes. However, its mechanism to initiate these genetic alterations is still unclear. AID can convert cytosine to uracil on either mRNA or DNA and is involved in DNA cleavage. Although these events are expected to take place in the nucleus, overexpressed AID was found predominantly in the cytoplasm. Here, we demonstrated that AID is a nucleocytoplasmic shuttling protein with a bipartite nuclear localization signal and a nuclear export signal in its N and C termini, respectively. In addition to previously identified genetic, structural, and biochemical similarities of AID with apolipoprotein B mRNA editing catalytic polypeptide 1, an RNA editing enzyme of ApoB100 mRNA, the present finding provides another aspect to their resemblance, suggesting that both may have homologous reaction mechanisms.
authors.affiliation: Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Satomi
authors.initials: S
authors.lastname: Ito
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nagaoka
authors.forename: Reiko
authors.initials: R
authors.lastname: Shinkura
authors.forename: Nasim
authors.initials: N
authors.lastname: Begum
authors.forename: Masamichi
authors.initials: M
authors.lastname: Muramatsu
authors.forename: Mikiyo
authors.initials: M
authors.lastname: Nakata
authors.forename: Tasuku
authors.initials: T
authors.lastname: Honjo
mesh_terms: D000071479:APOBEC-1 Deaminase; D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D003564:Cytidine Deaminase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D041681:NIH 3T3 Cells; D019913:Nuclear Localization Signals; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D000098830:AICDA (Activation-Induced Cytidine Deaminase)
chemical_list: D019913:Nuclear Localization Signals; D000098830:AICDA (Activation-Induced Cytidine Deaminase); D000071479:APOBEC-1 Deaminase; C000605089:APOBEC1 protein, human; C000605090:Apobec1 protein, mouse; D003564:Cytidine Deaminase