title: CRAC channel is inhibited by neomycin in a Ptdlns(4,5)P2-independent manner.
abstract: Depletion of intracellular Ca(2+) stores evokes store-operated Ca(2+) entry through the Ca(2+) release-activated Ca(2+) (CRAC) channels. In this study, we found that the store-operated Ca(2+) entry was inhibited by neomycin, an aminoglycoside that strongly binds phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). Patch clamp recordings revealed that neomycin blocked the CRAC currents reconstituted by co-expression of Orai1 and Stim1 in HEK293 cells. Using a rapamycin-inducible PtdIns(4,5)P2-specific phosphatase (Inp54p) system to manipulate the PtdIns(4,5)P2 in the plasma membrane, we found that the CRAC current was not altered by PtdIns(4,5)P2 depletion. This result suggests that PtdIns(4,5)P2 is not required for CRAC channel activity, and thereby, neomycin inhibits CRAC channels in a manner that is independent of neomycin-PtdIns(4,5)P2 binding.
authors: Department of Ultrasound, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China.
authors: Kun
authors: K
authors: Huang
authors: Xuemei
authors: X
authors: Wang
authors: Yanjun
authors: Y
authors: Liu
authors: Yi
authors: Y
authors: Zhao
mesh_terms: D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects*; D057809:HEK293 Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D009355:Neomycin / Q000494:pharmacology*; D009363:Neoplasm Proteins / Q000378:metabolism; D000071740:ORAI1 Protein; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D000071737:Stromal Interaction Molecule 1
chemical_list: D015220:Calcium Channels; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D000071740:ORAI1 Protein; C510746:ORAI1 protein, human; D019269:Phosphatidylinositol 4,5-Diphosphate; C103530:STIM1 protein, human; D000071737:Stromal Interaction Molecule 1; D009355:Neomycin
keywords: CRAC channel; Ca2+; Orai1; PtdIns(4,5)P2; Stim1; neomycin