title: Microscopic analysis of Orai-mediated store-operated calcium entry in cells with experimentally altered levels of amyloid precursor protein.
abstract: Familial Alzheimer's disease (FAD)-causing mutations in presenilins were shown to alter intracellular calcium dynamics, including store-operated calcium entry (SOCE). However, the involvement of FAD-linked amyloid precursor protein (APP) in SOCE remains controversial. Here, we used gain-of-function and loss-of-function approaches to shed light on this issue. We found that Jurkat cells, which exhibit prominent SOCE mediated by Orai channels, maintain low APP levels. The ectopic expression of APP, either with wildtype sequence or FAD-causing Swedish mutation, had no effect on SOCE induced by calcium store depletion with cyclopiazonic acid (CPA). The overproduction of C99 fragments, mimicking amyloidogenic processing of APP, also had no effect. Moreover, there was no alteration in the CPA-evoked SOCE upon APP knockdown in HeLa cells, which natively express 100-fold more APP than Jurkat cells. Consistently, we found no evidence for APP-dependent changes in the mRNA or protein levels of main SOCE components. Altogether, these results suggest that APP does not modulate Orai-dependent SOCE following quantitative calcium store depletion.
authors.affiliation: Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, 02-109, Warsaw, Poland. Electronic address: twegierski@iimcb.gov.pl.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Wegierski
authors.affiliation: Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, 02-109, Warsaw, Poland.
authors.forename: Kinga
authors.initials: K
authors.lastname: Gazda
authors.affiliation: Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, 02-109, Warsaw, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Kuznicki
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D009363:Neoplasm Proteins / Q000378:metabolism; D000071740:ORAI1 Protein / Q000378:metabolism*; D000071737:Stromal Interaction Molecule 1 / Q000378:metabolism
chemical_list: C545487:APP protein, human; D016564:Amyloid beta-Protein Precursor; D009363:Neoplasm Proteins; D000071740:ORAI1 Protein; C510746:ORAI1 protein, human; C103530:STIM1 protein, human; D000071737:Stromal Interaction Molecule 1; D002118:Calcium
keywords: Alzheimer's disease; Amyloid precursor protein; Calcium signaling; Capacitative calcium entry; Orai; Store-operated calcium entry