title: Novel Protein Kinase C-Mediated Control of Orai1 Function in  Invasive Melanoma.
abstract: The incidence of malignant melanoma, a cancer of the melanocyte cell lineage, has nearly doubled in the past 20 years. Wnt5A, akey driver of melanoma invasiveness, induces Ca2 signals. To understand how store-operated calcium entry (SOCE) contributes to Wnt5A-induced malignancy in melanoma models, we examined the expression and function of STIM1 and Orai1 in patient-derived malignant melanoma cells, previously characterized as either highly invasive (metastatic) or noninvasive. Using both fluorescence microscopy and electrophysiological approaches, we show that SOCE is greatly diminished in invasive melanoma compared to its level in noninvasive cell types. However, no loss of expression of any members of the STIM and Orai families was observed in invasive melanoma cells. Moreover, overexpressed wild-type STIM1 and Orai1 failed to restore SOCE in invasive melanoma cells, and we observed no defects in their localization before or after store depletion in any of the invasive celllines. Importantly, however, we determined that SOCE was restored by inhibition of protein kinase C, a known downstream target of Wnt5A. Furthermore, coexpression of STIM1 with an Orai1 mutant insensitive to protein kinase C-mediated phosphorylation fully restored SOCE in invasive melanoma. These findings reveal a level of control for STIM/Orai function in invasive melanoma not previously reported.
authors.forename: Robert
authors.initials: R
authors.lastname: Hooper
authors.forename: Xuexin
authors.initials: X
authors.lastname: Zhang
authors.forename: Marie
authors.initials: M
authors.lastname: Webster
authors.forename: Christina
authors.initials: C
authors.lastname: Go
authors.forename: Joseph
authors.initials: J
authors.lastname: Kedra
authors.forename: Katie
authors.initials: K
authors.lastname: Marchbank
authors.forename: Donald L
authors.initials: DL
authors.lastname: Gill
authors.forename: Ashani T
authors.initials: AT
authors.lastname: Weeraratna
authors.forename: Mohamed
authors.initials: M
authors.lastname: Trebak
authors.forename: Jonathan
authors.initials: J
authors.lastname: Soboloff
mesh_terms: D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008545:Melanoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009361:Neoplasm Invasiveness / Q000235:genetics / Q000473:pathology*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D000071740:ORAI1 Protein; D011493:Protein Kinase C / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D000071737:Stromal Interaction Molecule 1; D014407:Tumor Cells, Cultured; D051153:Wnt Proteins / Q000378:metabolism; D000071818:Wnt-5a Protein
chemical_list: D015220:Calcium Channels; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D000071740:ORAI1 Protein; C510746:ORAI1 protein, human; D011518:Proto-Oncogene Proteins; C103530:STIM1 protein, human; D000071737:Stromal Interaction Molecule 1; C085389:WNT5A protein, human; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; D011493:Protein Kinase C; D002118:Calcium