Biographical note of the first author: Hao ZHANG, male, born in 1981, Ph. D candidate, majoring in cell biology and proteomics Correspondence: Dr. Da-Cheng HE, Beijing Normal University, Key Laboratory of Cell Proliferation and Regulation of Ministry of Education, 19th Xinjiekouwai St. 100875, Beijing China. Fax: 8610-58805042. E-mail: dhe@bnu.edu.cn Correspondence: Dr. Xue-Yuan XIAO , Beijing Normal University, Key Laboratory of Cell Proliferation and Regulation of Ministry of Education, 19th Xinjiekouwai St. 100875, Beijing China. Fax: 8610-58805042. E-mail: xyxiao@bnu.edu.cn