title: Subcellular localization of CIAPIN1.
abstract: Cytokine-induced apoptosis inhibitor 1 (CIAPIN1) is a newly identified anti-apoptotic molecule. Our previous studies have demonstrated that CIAPIN1 is ubiquitously expressed in normal fetal and adult human tissues and confers multidrug resistance in gastric cancer cells, possibly by upregulating the expression of multidrug resistance gene 1 and multidrug resistance-related protein 1. However, fundamental biological functions of CIAPIN1 have not been elucidated. In this study, we first predicted the subcellular localization of CIAPIN1 with bioinformatic approaches and then characterized the intracellular localization of CIAPIN1 in both human and mouse cells by a combination of techniques including (a)immunohistochemistry and immunofluorescence, (b) His-tagged CIAPIN1 expression, and (c)subcellular fractionation and analysis of CIAPIN1 in the fractions by Western blotting. All methods produced consistent results; CIAPIN1 was localized in both the cytoplasm and the nucleus and was accumulated in the nucleolus. Bioinformatic prediction disclosed a putative nuclear localization signal and a putative nuclear export signal within both human and mouse CIAPIN1. These findings suggest that CIAPIN1 may undergo a cytoplasm-nucleus-nucleolus translocation.
authors.affiliation: State Key Laboratory of Cancer Biology, Institute of Digestive Diseases, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, Shaanxi Province, China.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Hao
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Li
authors.forename: Taidong
authors.initials: T
authors.lastname: Qiao
authors.forename: Rui
authors.initials: R
authors.lastname: Du
authors.forename: Guoyun
authors.initials: G
authors.lastname: Zhang
authors.forename: Daiming
authors.initials: D
authors.lastname: Fan
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002458:Cell Fractionation; D002460:Cell Line; D002478:Cells, Cultured; D003593:Cytoplasm / Q000737:chemistry*; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis* / Q000235:genetics; D051379:Mice; D041681:NIH 3T3 Cells; D009928:Organ Specificity; D012680:Sensitivity and Specificity; D013347:Subcellular Fractions / Q000737:chemistry*
chemical_list: C489114:CIAPIN1 protein, human; D047908:Intracellular Signaling Peptides and Proteins