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Updated: Jul 4, 2026
07:14
Subcellular Imaging of Neuronal Calcium Handling In Vivo
Published on: March 17, 2023
A distinct endosomal Ca2+/Mn2+ pump affects root growth through the secretory process
Xiyan Li1, Salil Chanroj, Zhongyi Wu
1Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815, USA.
Plant Physiology
|June 24, 2008
Summary
Arabidopsis thaliana calcium ATPase 3 (AtECA3) supports root growth and manganese detoxification. Its distinct role in post-Golgi compartments differs from ER-bound AtECA1, impacting protein secretion.
Area of Science:
- Plant Biology
- Cell Biology
- Molecular Biology
Background:
- Calcium ions (Ca2+) are crucial for protein processing, sorting, and secretion in eukaryotic cells.
- The specific roles of calcium transporters in plant secretory systems remain largely unknown.
- Arabidopsis thaliana possesses multiple Ca-ATPases, including AtECA3, with distinct characteristics.
Purpose of the Study:
- To investigate the function of Arabidopsis thaliana calcium ATPase 3 (AtECA3) in plant cells.
- To determine if AtECA3 plays a role in calcium and manganese transport and homeostasis.
- To elucidate the specific cellular localization and function of AtECA3 within the secretory pathway.
Main Methods:
- Functional expression of AtECA3 in a yeast mutant lacking Ca2+ pumps.
- Localization studies using green fluorescent protein (GFP)-tagged AtECA3 in yeast and Arabidopsis protoplasts.
- Analysis of T-DNA insertion mutants (eca3) for root growth, manganese sensitivity, and apoplastic protein secretion.
Main Results:
- AtECA3 expression in yeast conferred Ca2+-depleted growth and Mn2+ tolerance, localizing to intracellular membranes.
- In Arabidopsis, AtECA3-GFP partially colocalized with endosome/prevacuolar compartments.
- eca3 mutants exhibited reduced root growth, increased Mn2+ sensitivity, and altered apoplastic protein secretion compared to wild-type.
Conclusions:
- AtECA3 has a distinct function separate from the ER-localized AtECA1, supporting Ca2+-stimulated root growth.
- AtECA3 is essential for detoxification of excess manganese (Mn2+).
- AtECA3 likely operates in post-Golgi compartments, influencing membrane traffic and secretion to the vacuole and cell wall.
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