title: Light-induced exocytosis in cell development and differentiation.
abstract: Calcium-dependent exocytosis of fluorescently labeled single secretory vesicles in PC12 cells and primary embryonic telencephalon cells can be triggered by illumination with visible light and imaged by TIRF or epifluorescence microscopy. Opsin 3 was identified by quantitative PCR expression analysis as the putative light receptor molecule for light-induced exocytosis. In primary chicken telencephalon cells, light-induced exocytosis is restricted to a specific period during embryonic development, and involves fusion of rather large vesicles. Strictly calcium-dependent exocytosis starts after a delay of a few seconds of illumination and lasts for up to 2 min. We analyzed the frequency, time course and spatial distribution of exocytotic events. Exocytosis in PC12 cells and telencephalon cells occurs at the periphery or the interface between dividing cells, and the duration of single secretion events varies considerably. Our observation strongly supports the idea that light induced exocytosis is most likely a mechanism for building plasma membrane during differentiation, development and proliferation rather than for calcium-dependent neurotransmitter release.
authors.affiliation: Department of Psychiatry, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany. andreas.henkel@psych.imed.uni-erlangen.de
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Henkel
authors.forename: Irene
authors.initials: I
authors.lastname: Upmann
authors.forename: Christina R
authors.initials: CR
authors.lastname: Bartl
authors.forename: Dominikus
authors.initials: D
authors.lastname: Bönsch
authors.forename: Cornelia
authors.initials: C
authors.lastname: Reichardt
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Maler
authors.forename: Michael
authors.initials: M
authors.lastname: Nürnberger
authors.forename: Richard
authors.initials: R
authors.lastname: Umstätter
authors.forename: Udo
authors.initials: U
authors.lastname: Reulbach
authors.forename: Johannes
authors.initials: J
authors.lastname: Kornhuber
authors.forename: Jens
authors.initials: J
authors.lastname: Wiltfang
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology / Q000528:radiation effects; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002645:Chickens; D005089:Exocytosis / Q000502:physiology*; D008027:Light; D008561:Membrane Fusion; D008856:Microscopy, Fluorescence; D016716:PC12 Cells; D010782:Photolysis; D051381:Rats; D015398:Signal Transduction
chemical_list: D002118:Calcium