Endoplasmic Reticulum (ER) Stress Enhances Tip60 (A Histone Acetyltransferase) Binding to the Concanavalin A
Eun Jeoung Lee2, Sung Hwa Shin1, Sunghee Hyun2, Jaesun Chun3, Sang Sun Kang*, 1
1 Department of Biology Education, Chungbuk National University, Gaeshin-dong, Heungdok-gu, Cheongju, Chungbuk, 361-763, Republic of Korea.
2 Department of Pre-medicine, Eulji University School of Medicine, Daejeon 301-832, Republic of Korea
3 Department of Biology Education, Korea National University of Education, Chongwon, Chungbuk 363-791, Republic of Korea
Herein, we report that the concanavalin A binding of Tip60 (a target of the human immunodeficiency virus type 1-encoded transactivator Tat interacting protein 60 KD; a histone acetyltransferase; HAT) is enhanced as the result of endoplasmic reticulum (ER) stress. The cell expression of Tip60 combined with site-directed mutagenesis analysis was used to identify the glutamine 324 residue as the lecithin binding (Concanavalin A; Con A) site. The Tip60 N324A mutant strain, which seems to be the Con A binding-deficient, was attenuated the protein-protein interactions with FE65 and its protein stability, but its ability of G0-G1 cell cycle arrest was not interrupted. Interestingly, both HAT activity and the nuclear localization of Tip60 N324A mutant were enhanced than those of Tip60 WT. Thus, our results indicate that the Con A binding deficient of Tip60 seems to be one of the most pivotal posttranslational modifications (such as N-glycosylation) for its functional regulation signal, which is generated in response to ER stress.
Keyword: Tip60, N-glycosylation, ER stress, HAT, Cell cycle.
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