title: TRPM7 triggers Ca2+ sparks and invadosome formation in neuroblastoma cells.
abstract: Cell migration depends on the dynamic formation and turnover of cell adhesions and is tightly controlled by actomyosin contractility and local Ca2+ signals. The divalent cation channel TRPM7 (Transient Receptor Potential cation channel, subfamily Melastatin, member 7) has recently received much attention as a regulator of cell adhesion, migration and (localized) Ca2+ signaling. Overexpression and knockdown of TRPM7 affects actomyosin contractility and the formation of cell adhesions such as invadosomes and focal adhesions, but the role of TRPM7-mediated Ca2+ signals herein is currently not understood. Using Total Internal Reflection Fluorescence (TIRF) Ca2+ fluorometry and a novel automated analysis routine we have addressed the role of Ca2+ in the control of invadosome dynamics in N1E-115 mouse neuroblastoma cells. We find that TRPM7 promotes the formation of highly repetitive and localized Ca2+ microdomains or "Ca2+ sparking hotspots" at the ventral plasma membrane. Ca2+ sparking appears strictly dependent on extracellular Ca2+ and is abolished by TRPM7 channel inhibitors such as waixenicin-A. TRPM7 inhibition also induces invadosome dissolution. However, invadosome formation is (functionally and spatially) dissociated from TRPM7-mediated Ca2+ sparks. Rather, our data indicate that TRPM7 affects actomyosin contractility and invadosome formation independent of Ca2+ influx.
authors.affiliation: Division of Cell Biology I, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands.
authors.forename: Daan
authors.initials: D
authors.lastname: Visser
authors.forename: Michiel
authors.initials: M
authors.lastname: Langeslag
authors.forename: Katarzyna M
authors.initials: KM
authors.lastname: Kedziora
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Klarenbeek
authors.forename: Alwin
authors.initials: A
authors.lastname: Kamermans
authors.forename: F David
authors.initials: FD
authors.lastname: Horgen
authors.forename: Andrea
authors.initials: A
authors.lastname: Fleig
authors.forename: Frank N
authors.initials: FN
authors.lastname: van Leeuwen
authors.forename: Kees
authors.initials: K
authors.lastname: Jalink
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D004224:Diterpenes / Q000494:pharmacology; D051379:Mice; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D050053:TRPM Cation Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000085:Acetates; D004224:Diterpenes; D034741:RNA, Small Interfering; D050053:TRPM Cation Channels; C568854:waixenicin A; D000205:Actomyosin; C421903:Trpm7 protein, mouse; D002118:Calcium
keywords: 2-APB; 2-aminoethyl diphenylborinate; Adhesion; BK; Ca(2+) imaging; Ca(2+) signaling; ECM; FA; FC; Invadosome; TIRF; TIRF microscopy; TRPM7; Total Internal Reflection Fluorescence (microscopy); Transient Receptor Potential cation channel, subfamily Melastatin, member 7; bradykinin; extracellular matrix; focal adhesion; focal complex