Binding of human BiP to the ER stress transducers IRE1 and PERK requires ATP

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• 作者：Si Nga Sou^a ; ^{si.sou07@imperial.ac.uk} ; Kristina M. Ilieva^b ; Karen M. Polizzi^b ; ^{k.polizzi@imperial.ac.uk}
• 关键词：ADP ; adenosine diphosphate ; ATF6 ; activating transcription factor 6 ; ATP ; adenosine triphosphate ; BiP ; immunoglobulin binding protein ; ER ; endoplasmic reticulum ; GST ; glutathione-S-transferase ; IRE1 ; inositol requiring enzyme 1 ; PERK ; PKR-like ER kinase
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2012
• 期刊代码：159_0006291x
• 类别：bio
• 出版时间：6 April, 2012
• 卷：420
• 期：2
• 页码：473-478
• 文件大小：557 K

摘要

ER stress is activated in a number of important diseases such as diabetes, cancer, and neurodegeneration, but the molecular interactions governing the response are still being elucidated. In the absence of stress, protein complexes exist between the ER-resident chaperone BiP and three transmembrane signalling molecules which are responsible for signal transmission. Previous results suggested that cofactors might participate in these interactions, but the molecular details are not well understood. We coexpressed BiP and the lumenal domains of each of the three ER stress transducers and copurified the complexes in the presence of ATP and ADP in order to better understand how the complex is formed. ATP, but not ADP, was required to isolate the BiP-IRE1 and the BiP-PERK complexes, but the BiP-ATF6 complex was purified in all conditions tested. Based on the results, we hypothesize that in contrast to its mode of binding ATF6 and unfolded proteins, BiP binds to IRE1 and PERK in a different manner.