title: Nuclear calmodulin responds rapidly to calcium influx at the plasmalemma.
abstract: We have studied the rate and extent of calcium binding to calmodulin in neuronal cytosol and nucleus during brief calcium influx across the plasmalemma. Rat sensory neurones were whole-cell patch clamped using a pipette containing a fluorescent analogue of calmodulin that reports when it has bound calcium. Cytosolic and nuclear signals were separated using a confocal microscope. Plasmalemmal calcium influx during a one second depolarization that activated L type calcium channels caused large fractions of calmodulin in both the cytosol and nucleus to bind calcium. Thus, contrary to previous predictions, nuclear processes that require the calcium:calmodulin complex will be activated readily by even brief cell stimulation.
authors.affiliation: Department of Physiology, University College London, UK.
authors.forename: F
authors.initials: F
authors.lastname: Zimprich
authors.forename: K
authors.initials: K
authors.lastname: Torok
authors.forename: S R
authors.initials: SR
authors.lastname: Bolsover
mesh_terms: D000200:Action Potentials; D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D020746:Calcium Channels, L-Type; D002147:Calmodulin / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004058:Diffusion; D007091:Image Processing, Computer-Assisted; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009475:Neurons, Afferent / Q000378:metabolism* / Q000502:physiology; D018408:Patch-Clamp Techniques; D051381:Rats
chemical_list: D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D002147:Calmodulin; D009419:Nerve Tissue Proteins; D002118:Calcium