Poster: Temperature responses

Abs # 123: AtBAG6, a Bcl2-associated athanogene-family protein in Arabidopsis, interacts with Calmodulin and induces cell death in yeast

Presenter:	Kang, Chang Ho , jacobh69@hotmail.com
Authors	Kang, Chang Ho  (A) (C)  Jung, Won Yong  (B) (C)  Kang, Yun Hwan  (B) (C)  Baek, Donh Won  (B) (C)  Jung, Jae Cheol  (B) (C)  Shin, Dong Jin  (B) (C)  Chung, Woo Sik  (A) (C)  Cho, Moo Je  (B) (C)  Yun, Dae Jin  (A) (C)
Affiliations:	(A): Environmental Biotechnology Research Center (B): Division of Applied Life Science (BK21 Program) (C): Plant Molecular Biology and Biotechnology Research Center

To study the contribution of the ¡®IQ-motif¡¯ (a Ca2+-independent CaM-binding site) in the signal transduction, especially, programmed cell death (PCD) in plant, we cloned AtBAG6 cDNA using a protein-protein interaction-based screening of a cDNA expression library from Arabidopsis. The encoded protein of this gene consists of 1043 amino acids and contained an IQ-motif and a BAG-domain in the middle of the sequence. AtBAG6 gene expression was highly increased in the condition of high temperature and by the treatments of hydrogen peroxide or salicylic acid. Like a mammalian proapoptotic protein, BAX, AtBAG6 was able to kill cell when over-expressed in yeast. As results of domain mapping, we identified the 135 amino-acids stretch named as PDD (Plant Death Domain) which was sufficient to kill cell. Based on mutagenesis approaches, the conservation of IQ-motif in PDD was necessary for the lethality of the protein in yeast cell. In this report we suggest that the IQ-motif in plant may regulate the cell death mechanism. [This work was supported by a grant from the Korea Science and Engineering Foundation (KOSEF) to the Environmental Biotechnology Research Center]