title: Control of mitochondrial motility and distribution by the calcium signal: a homeostatic circuit.
abstract: Mitochondria are dynamic organelles in cells. The control of mitochondrial motility by signaling mechanisms and the significance of rapid changes in motility remains elusive. In cardiac myoblasts, mitochondria were observed close to the microtubular array and displayed both short- and long-range movements along microtubules. By clamping cytoplasmic [Ca2+] ([Ca2+]c) at various levels, mitochondrial motility was found to be regulated by Ca2+ in the physiological range. Maximal movement was obtained at resting [Ca2+]c with complete arrest at 1-2 microM. Movement was fully recovered by returning to resting [Ca2+]c, and inhibition could be repeated with no apparent desensitization. The inositol 1,4,5-trisphosphate- or ryanodine receptor-mediated [Ca2+]c signal also induced a decrease in mitochondrial motility. This decrease followed the spatial and temporal pattern of the [Ca2+]c signal. Diminished mitochondrial motility in the region of the [Ca2+]c rise promotes recruitment of mitochondria to enhance local Ca2+ buffering and energy supply. This mechanism may provide a novel homeostatic circuit in calcium signaling.
authors.affiliation: Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors.forename: Muqing
authors.initials: M
authors.lastname: Yi
authors.forename: David
authors.initials: D
authors.lastname: Weaver
authors.forename: György
authors.initials: G
authors.lastname: Hajnóczky
mesh_terms: D008841:Actin Cytoskeleton / Q000648:ultrastructure; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D002460:Cell Line; D003595:Cytoplasmic Streaming / Q000502:physiology*; D006706:Homeostasis / Q000235:genetics; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008564:Membrane Potentials / Q000502:physiology; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D008928:Mitochondria / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D032386:Myoblasts, Cardiac / Q000378:metabolism* / Q000648:ultrastructure; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism
chemical_list: D019837:Ryanodine Receptor Calcium Release Channel; D002118:Calcium