In vivo analysis of the calcium signature in the plant Golgi apparatus reveals unique dynamics

Cell Calcium. 2012 Nov;52(5):397-404. doi: 10.1016/j.ceca.2012.06.008. Epub 2012 Jul 23.

Abstract

The Golgi apparatus is thought to play a role in calcium homeostasis in plant cells. However, the calcium dynamics in this organelle is unknown in plants. To monitor the [Ca2+]Golgiin vivo, we obtained and analyzed Arabidopsis thaliana plants that express aequorin in the Golgi. Our results show that free [Ca2+] levels in the Golgi are higher than in the cytosol (0.70 μM vs. 0.05 μM, respectively). Stimuli such as cold shock, mechanical stimulation and hyperosmotic stress, led to a transient increase in cytosolic calcium; however, no instant change in the [Ca2+]Golgi concentration was detected. Nevertheless, a delayed increase in the [Ca2+]Golgi up to 2-3 μM was observed. Cyclopiazonic acid and thapsigargin inhibited the stimuli-induced [Ca2+]Golgi increase, suggesting that [Ca2+]Golgi levels are dependent upon the activity of Ca2+-ATPases. Treatment of these plants with the synthetic auxin analog, 2,4-dichlorophenoxy acetic acid (2,4-D), produced a slow decrease of free calcium in the organelle. Our results indicate that the plant Golgi apparatus is not involved in the generation of cytosolic calcium transients and exhibits its own dynamics modulated in part by the activity of Ca2+ pumps and hormones.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2,4-Dichlorophenoxyacetic Acid / chemistry
  • 2,4-Dichlorophenoxyacetic Acid / pharmacology
  • Aequorin / genetics
  • Aequorin / metabolism*
  • Arabidopsis / physiology*
  • Calcium / metabolism*
  • Calcium Signaling / drug effects
  • Calcium Signaling / genetics
  • Calcium-Transporting ATPases / antagonists & inhibitors
  • Cytosol / drug effects
  • Cytosol / metabolism*
  • Golgi Apparatus / drug effects
  • Golgi Apparatus / genetics
  • Golgi Apparatus / metabolism*
  • Indoleacetic Acids / chemistry
  • Indoles / pharmacology
  • Plant Growth Regulators / chemistry
  • Plant Growth Regulators / pharmacology
  • Thapsigargin / pharmacology

Substances

  • Indoleacetic Acids
  • Indoles
  • Plant Growth Regulators
  • 2,4-Dichlorophenoxyacetic Acid
  • Aequorin
  • Thapsigargin
  • Calcium-Transporting ATPases
  • Calcium
  • cyclopiazonic acid