2. Academic Validation
  3. Proteomic mapping of ER-PM junctions identifies STIMATE as a regulator of Ca²⁺ influx

Proteomic mapping of ER-PM junctions identifies STIMATE as a regulator of Ca²⁺ influx

  • Nat Cell Biol. 2015 Oct;17(10):1339-47. doi: 10.1038/ncb3234.
Ji Jing 1,  Lian He 1,  Aomin Sun 2,  Ariel Quintana 3,  Yuehe Ding 4,  Guolin Ma 1,  Peng Tan 1,  Xiaowen Liang 1,  Xiaolu Zheng 5,  Liangyi Chen 5,  Xiaodong Shi 6,  Shenyuan L Zhang 7,  Ling Zhong 1,  Yun Huang 1,  Meng-Qiu Dong 4,  Cheryl L Walker 1,  Patrick G Hogan 3,  Youjun Wang 2,  Yubin Zhou 1 7
Affiliations

Affiliations

  • 1 Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030, USA.
  • 2 Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
  • 3 Division of Signaling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA.
  • 4 National Institute of Biological Sciences, Beijing 102206, China.
  • 5 Institute of Molecular Medicine, Peking University, Beijing 100871, China.
  • 6 Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, USA.
  • 7 Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, Texas 76504, USA.
PMID: 26322679 DOI: 10.1038/ncb3234
Abstract

Specialized junctional sites that connect the plasma membrane (PM) and endoplasmic reticulum (ER) play critical roles in controlling lipid metabolism and Ca(2+) signalling. Store-operated Ca(2+) entry mediated by dynamic STIM1-ORAI1 coupling represents a classical molecular event occurring at ER-PM junctions, but the protein composition and how previously unrecognized protein regulators facilitate this process remain ill-defined. Using a combination of spatially restricted biotin labelling in situ coupled with mass spectrometry and a secondary screen based on bimolecular fluorescence complementation, we mapped the proteome of intact ER-PM junctions in living cells without disrupting their architectural integrity. Our approaches led to the discovery of an ER-resident multi-transmembrane protein that we call STIMATE (STIM-activating enhancer, encoded by TMEM110) as a positive regulator of Ca(2+) influx in vertebrates. STIMATE physically interacts with STIM1 to promote STIM1 conformational switch. Genetic depletion of STIMATE substantially reduces STIM1 puncta formation at ER-PM junctions and suppresses the Ca(2+)-NFAT signalling. Our findings enable further genetic studies to elucidate the function of STIMATE in normal physiology and disease, and set the stage to uncover more uncharted functions of hitherto underexplored ER-PM junctions.

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