In planta, only very limited information is available about how the endoplasmic reticulum (ER) contributes to cellular Ca2+ dynamics and homeostasis. Here we report the generation of an ER-targeted Cameleon reporter protein suitable for analysis of Ca2+ accumulation and dynamics in the lumen of the ER in plant cells. Using stably transformed Arabidopsis plants expressing this reporter protein we observed a transiently enhanced accumulation of Ca2+ in the ER in response to stimuli inducing cytosolic Ca2+ rises in root tip cells. In all experimental conditions ER Ca2+ dynamics were substantially different from those monitored in the cytosol. A pharmacological approach enabled us to evaluate the contribution of the different ER-resident Ca2+-ATPase classes in the regulation of the ER Ca2+ homeostasis. Taken together, our results do not provide evidence for a role of the ER as a major source that releases Ca2+ for stimulus-induced increases in cytosolic Ca2+ concentration. Instead, our results show that the luminal ER Ca2+ elevations typically follow cytosolic ones, but with distinct dynamics. These findings suggest fundamental differences for the function of the ER in cellular Ca2+ homeostasis in plants and animals.

Analyses of Ca2+ accumulation and dynamics in the endoplasmic reticulum of Arabidopsis root cells using a genetically encoded Cameleon sensor / M.C. Bonza, G. Loro, S. Behera, A. Wong, J. Kudla, A. Costa. - In: PLANT PHYSIOLOGY. - ISSN 0032-0889. - 163:3(2013), pp. 1230-1241.

Analyses of Ca2+ accumulation and dynamics in the endoplasmic reticulum of Arabidopsis root cells using a genetically encoded Cameleon sensor

M.C. Bonza
Primo
;
G. Loro
Secondo
;
A. Costa
2013

Abstract

In planta, only very limited information is available about how the endoplasmic reticulum (ER) contributes to cellular Ca2+ dynamics and homeostasis. Here we report the generation of an ER-targeted Cameleon reporter protein suitable for analysis of Ca2+ accumulation and dynamics in the lumen of the ER in plant cells. Using stably transformed Arabidopsis plants expressing this reporter protein we observed a transiently enhanced accumulation of Ca2+ in the ER in response to stimuli inducing cytosolic Ca2+ rises in root tip cells. In all experimental conditions ER Ca2+ dynamics were substantially different from those monitored in the cytosol. A pharmacological approach enabled us to evaluate the contribution of the different ER-resident Ca2+-ATPase classes in the regulation of the ER Ca2+ homeostasis. Taken together, our results do not provide evidence for a role of the ER as a major source that releases Ca2+ for stimulus-induced increases in cytosolic Ca2+ concentration. Instead, our results show that the luminal ER Ca2+ elevations typically follow cytosolic ones, but with distinct dynamics. These findings suggest fundamental differences for the function of the ER in cellular Ca2+ homeostasis in plants and animals.
calmodulin-regulated CA2+-atpase; fluorescent indicators; glutamate-receptor; calcium oscillations; plasma-membrane; higher-plants; guard-cells; channels; thaliana; growth
Settore BIO/04 - Fisiologia Vegetale
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/227689
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