ERp44 C160S/C212S mutants regulate IP3R1 channel activity
ERp44 C160S/C212S mutants regulate IP3R1 channel activity
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DOI：
10.1007/s13238-011-1116-0
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发表时间：
2011-12-01
期刊：
影响因子：
21.1
通讯作者：
Ji, Guangju
中科院分区：
文献类型：
--
作者：
Pan, Congyan;Zheng, Ji;Ji, Guangju
先前的研究表明，ERp44 通过 IP3R1 抑制肌醇 1,4,5-三磷酸 (IP3) 诱导的 Ca2+ 释放 (IICR)，但其机制在很大程度上仍未被探索。本研究以细胞外ATP诱导细胞内钙瞬变作为IICR模型，进行了Ca2+成像、pull down实验和Western blotting实验。我们发现细胞外 ATP 通过 IP(3)Rs (IICR) 诱导钙瞬变，并且在 ERp44 过表达的 Hela 细胞中 IICR 显着降低。与ERp44相比，ERp44的C160S/C212S突变体对IICR的抑制作用显着降低，但C29S/T396A/Delta T(331-377)突变体对IICR的抑制作用没有显着降低。然而，ERp44 C160S/C212S 突变增强了 ERp44 与 IP3R1 (1L3V) 的 L3V 结构域的结合能力。综上所述，这些结果表明 ERp44 的突变体 C160/C212 可以更紧密地结合 IP3R1，但在 Hela 细胞中表现出对 IP3R1 通道活性的弱抑制。
Previous studies have indicated that ERp44 inhibits inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ release (IICR) via IP3R1, but the mechanism remains largely unexplored. Using extracellular ATP to induce intracellular calcium transient as an IICR model, Ca2+ image, pull down assay, and Western blotting experiments were carried out in the present study. We found that extracellular ATP induced calcium transient via IP(3)Rs (IICR) and the IICR were markedly decreased in ERp44 over-expressed Hela cells. The inhibitory effect of C160S/C212S but not C29S/T396A/Delta T(331-377) mutants of ERp44 on IICR were significantly decreased compared with ERp44. However, the binding capacity of ERp44 to L3V domain of IP3R1 (1L3V) was enhanced by ERp44 C160S/C212S mutation. Taken together, these results suggest that the mutants of ERp44, C160/C212, can more tightly bind to IP3R1 but exhibit a weak inhibition of IP3R1 channel activity in Hela cells.