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Digitoxin Suppresses Store Operated Calcium Entry by Modulating Phosphorylation and the Pore Region of Orai1.

Abstract

BACKGROUND

Store-operated calcium entry (SOCE), primarily mediated by Orai1 and stromal interaction molecule 1 (STIM1), is a major Ca2+ influx pathway that has been linked to human diseases including myopathy, epilepsy, immunodeficiency, and cancer. Despite of the recent rapid progress of dissecting molecular mechanisms underlying SOCE activation, the development of therapies against dysfunctional SOCE significantly lags behind, partly due to the lack of more specific pharmacological tools and poor understanding of currently available SOCE modifiers, including the a newly identified SOCE inhibitor, digitoxin.

OBJECTIVE AND METHODS

Capitalizing on Ca2+ imaging and pharmacological tools, we aimed to systemically delineate the mechanism of action of digitoxin by defining how it impinges on Orai1 to exert its suppressive effect on SOCE.

RESULTS

The SOCE-suppressive function of digitoxin is dependent on S27-S30 residues of wild-type Orai1. With 8h-incubation of digitoxin with STIM1-prebound Orai1 or a constitutively active mutant Orai1-ANSGA, its inhibition was no longer dependent on S27-S30 residues. Instead, the inhibition may involve the pore region of Orai1 channels, as V102C mutant at the pore region would greatly diminish or abolish the inhibition on pre-activated Orai1.

CONCLUSIONS

Our study identified two regions that are critical for the inhibition on Orai1 channels, providing valuable hotspots for future design of SOCE inhibitors.

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  • Authors+Show Affiliations

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    Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.

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    Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.

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    Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.

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    Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.

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    Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.

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    Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, United States.

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    Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, United States.

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    Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.

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    Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.

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    Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, United States.

    ,

    Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.

    Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.

    Source

    Current molecular medicine 18:6 2018 pg 392-399

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't
    Research Support, N.I.H., Extramural

    Language

    eng

    PubMed ID

    30421677

    Citation

    Zhou, Lijuan, et al. "Digitoxin Suppresses Store Operated Calcium Entry By Modulating Phosphorylation and the Pore Region of Orai1." Current Molecular Medicine, vol. 18, no. 6, 2018, pp. 392-399.
    Zhou L, Chi X, Zhu Y, et al. Digitoxin Suppresses Store Operated Calcium Entry by Modulating Phosphorylation and the Pore Region of Orai1. Curr Mol Med. 2018;18(6):392-399.
    Zhou, L., Chi, X., Zhu, Y., Zhang, T., Liu, J., Ma, G., ... Wang, Y. (2018). Digitoxin Suppresses Store Operated Calcium Entry by Modulating Phosphorylation and the Pore Region of Orai1. Current Molecular Medicine, 18(6), pp. 392-399. doi:10.2174/1566524018666181113111316.
    Zhou L, et al. Digitoxin Suppresses Store Operated Calcium Entry By Modulating Phosphorylation and the Pore Region of Orai1. Curr Mol Med. 2018;18(6):392-399. PubMed PMID: 30421677.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Digitoxin Suppresses Store Operated Calcium Entry by Modulating Phosphorylation and the Pore Region of Orai1. AU - Zhou,Lijuan, AU - Chi,Xiangxiang, AU - Zhu,Yaping, AU - Zhang,Tian, AU - Liu,Jindou, AU - Ma,Guolin, AU - He,Lian, AU - Zhang,Shuce, AU - Gao,Ping, AU - Zhou,Yubin, AU - Liu,Jin, AU - Wang,Youjun, PY - 2018/08/15/received PY - 2018/10/26/revised PY - 2018/11/07/accepted PY - 2018/11/14/pubmed PY - 2018/11/14/medline PY - 2018/11/14/entrez KW - Calcium signalling KW - Orai1 KW - SOCE KW - digitoxin KW - fluorescence imaging KW - phosphorylation. SP - 392 EP - 399 JF - Current molecular medicine JO - Curr. Mol. Med. VL - 18 IS - 6 N2 - BACKGROUND: Store-operated calcium entry (SOCE), primarily mediated by Orai1 and stromal interaction molecule 1 (STIM1), is a major Ca2+ influx pathway that has been linked to human diseases including myopathy, epilepsy, immunodeficiency, and cancer. Despite of the recent rapid progress of dissecting molecular mechanisms underlying SOCE activation, the development of therapies against dysfunctional SOCE significantly lags behind, partly due to the lack of more specific pharmacological tools and poor understanding of currently available SOCE modifiers, including the a newly identified SOCE inhibitor, digitoxin. OBJECTIVE AND METHODS: Capitalizing on Ca2+ imaging and pharmacological tools, we aimed to systemically delineate the mechanism of action of digitoxin by defining how it impinges on Orai1 to exert its suppressive effect on SOCE. RESULTS: The SOCE-suppressive function of digitoxin is dependent on S27-S30 residues of wild-type Orai1. With 8h-incubation of digitoxin with STIM1-prebound Orai1 or a constitutively active mutant Orai1-ANSGA, its inhibition was no longer dependent on S27-S30 residues. Instead, the inhibition may involve the pore region of Orai1 channels, as V102C mutant at the pore region would greatly diminish or abolish the inhibition on pre-activated Orai1. CONCLUSIONS: Our study identified two regions that are critical for the inhibition on Orai1 channels, providing valuable hotspots for future design of SOCE inhibitors. SN - 1875-5666 UR - https://www.unboundmedicine.com/medline/citation/30421677/Digitoxin_Suppresses_Store_Operated_Calcium_Entry_by_Modulating_Phosphorylation_and_the_Pore_Region_of_Orai1 L2 - http://www.eurekaselect.com/167294/article DB - PRIME DP - Unbound Medicine ER -