| Summary: | 碩士 === 國立臺灣海洋大學 === 生物科技研究所 === 98 === BNIP3 is a BH3-only pro-apoptotic member of the Bcl-2 family with a C-terminal transmembrane (TM) domain, which mediates cell death by membrane insertion through TM domain that directs the protein to mitochondrial and endoplasmic reticular (ER) membranes. Previous studies have demonstrated that calcium ionophore can activate protein kinase C (PKC) to phosphorylate BNIP3 and to promote BNIP3 accumulation in cell. In this study, BNIP3 involved in A23187-induced death in Neuro2a cells. A23187, a calcium ionophore, can result in ER stress and apoptosis in Neuro2a cells. Treatment of Neuro2a cells with A23187 up-regulated BNIP3, and overexpression of BNIP3ΔTM blocked the A23187-induced cell death, showing that A23187-induced apoptosis may be through BNIP3. While overexpressed BNIP3, BNIP3 colocalized with MitoCapture in mitochondrial outer membrane and resulted in mitochondrial dysfunction. Furthermore, A23187 induced the expression of GRP78 protein, which is a maker protein of endoplasmic reticulum (ER) stress, and the expression is suppressed by BNIP3ΔTM. Our finding showed that A23187-induced ER stress mediated by BNIP3. Pre-treated chelerythrine (PKC inhibitor) reduces A23187-induced cell death and also decreased GRP78 expression. These results showed that A23187 causes BNIP3 accumulation via the activation of PKC and BNIP3 mediated A23187-induced cell death by inducing ER stress and
mitochondrial dysfunction in Neuro2a cells.
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