首页 | 本学科首页   官方微博 | 高级检索  
   检索      


STIM1 and STIM2 are located in the acidic Ca2+ stores and associates with Orai1 upon depletion of the acidic stores in human platelets
Authors:Zbidi Hanene  Jardin Isaac  Woodard Geoffrey E  Lopez Jose J  Berna-Erro Alejandro  Salido Ginés M  Rosado Juan A
Institution:Department of Physiology (Cell Physiology Research Group) University of Extremadura, 10003 Cáceres, Spain.
Abstract:Mammalian cells accumulate Ca2+ into agonist-sensitive acidic organelles, vesicles that possess a vacuolar proton-ATPase. Acidic Ca2+ stores include secretory granules and lysosome-related organelles. Current evidence clearly indicates that acidic Ca2+ stores participate in cell signaling and function, including the activation of store-operated Ca2+ entry in human platelets upon depletion of the acidic stores, although the mechanism underlying the activation of store-operated Ca2+ entry controlled by the acidic stores remains unclear. STIM1 has been presented as the endoplasmic reticulum Ca2+ sensor, but its role sensing intraluminal Ca2+ concentration in the acidic stores has not been investigated. Here we report that STIM1 and STIM2 are expressed in the lysosome-related organelles and dense granules in human platelets isolated by immunomagnetic sorting. Depletion of the acidic Ca2+ stores using the specific vacuolar proton-ATPase inhibitor, bafilomycin A1, enhanced the association between STIM1 and STIM2 as well as between these proteins and the plasma membrane channel Orai1. Depletion of the acidic Ca2+ stores also induces time-dependent co-immunoprecipitation of STIM1 with the TRPC proteins hTRPC1 and hTRPC6, as well as between Orai1 and both TRPC proteins. In addition, bafilomycin A1 enhanced the association between STIM2 and SERCA3. These findings demonstrate the location of STIM1 and STIM2 in the acidic Ca2+ stores and their association with Ca2+ channels and ATPases upon acidic stores discharge.
Keywords:Calcium Channels  Calcium Intracellular Release  Platelet  Protein-Protein Interactions  Signal Transduction  Orai1  STIM1  STIM2  hTRPC1  hTRPC6  Calcium Entry  Acidic Ca2+ Stores  Human Platelets
本文献已被 PubMed 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号