title: IP3 dependent Ca2+ signals in muscle cells are involved in regulation of gene expression.
abstract: Potassium depolarization of cultured muscle cells was employed to study cellular responses linked to calcium signaling. Events occurring after depolarization include i) A transient increase of the IP3 mass (2-10s); ii) A slow calcium transient (5 to 25s) that propagates as a low concentration wave along the myotube showing a distinct calcium transient at the level of cell nuclei. Due to the presence of IP3 receptors both in the SR (A-band region) and in the nuclear envelope, these two events appear to be related; iii) Phosphorylation of mitogen activated kinases (ERK 1/2) and of the transcription factor CREB (30 s-10 min), as well as expression of the early genes c-fos, c-jun and egr-1 mRNA (5-15 min). Several independent pieces of evidence, including results obtained using inhibitors specific for individual steps, allowed us to connect these in a sequential manner. As the same type of signaling cascade can be triggered by oxidants, neurotransmitters and hormones, the ensemble of results allows us to propose a general model to describe signaling events that link membrane stimulation to regulation of gene transcription in skeletal muscle cells.
authors.affiliation: Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile Casilla 70005, Santiago 6530499, Chile. ejaimovi@machi.med.uchile.cl
authors.forename: Enrique
authors.initials: E
authors.lastname: Jaimovich
authors.forename: María Angélica
authors.initials: MA
authors.lastname: Carrasco
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism / Q000502:physiology*; D002127:Calcium Isotopes; D020013:Calcium Signaling / Q000502:physiology*; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D005786:Gene Expression Regulation; D017781:Genes, Immediate-Early; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018482:Muscle, Skeletal / Q000166:cytology / Q000502:physiology*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism / Q000502:physiology*; D019837:Ryanodine Receptor Calcium Release Channel / Q000502:physiology; D014158:Transcription, Genetic
chemical_list: D015220:Calcium Channels; D002127:Calcium Isotopes; D017362:Cyclic AMP Response Element-Binding Protein; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D019837:Ryanodine Receptor Calcium Release Channel; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium