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Updated: Aug 12, 2026
07:51
Pull-down of Calmodulin-binding Proteins
Published on: January 23, 2012
Maize cap1 encodes a novel SERCA-type calcium-ATPase with a calmodulin-binding domain
1Department of Crop Sciences, University of Illinois, Urbana and the United States Department of Agriculture/Agricultural Research Service, Soybean/Maize Germplasm, Pathology and Genetics Unit, Urbana, Illinois 61801, USA. subbaiah@uiuc.edu
The Journal of Biological Chemistry
|April 20, 2000
Summary
Researchers identified a novel calmodulin-regulated calcium-ATPase (Ca2+-ATPase) in maize roots, named CAP1. This protein functions in calcium transport and is crucial for maize cells under oxygen-deprived conditions.
Area of Science:
- Plant molecular biology
- Ion transport mechanisms
- Biochemistry
Background:
- Calcium pumps (Ca2+-ATPases) are vital for maintaining cellular calcium homeostasis.
- Understanding plant Ca2+-ATPase function is crucial, especially under stress conditions like anoxia.
- Calmodulin (CaM) is a key calcium-binding protein regulating various cellular processes.
Purpose of the Study:
- To isolate and characterize a novel calcium pump from maize roots.
- To investigate the functional properties and regulation of the identified maize Ca2+-ATPase.
- To determine the role of this pump in maize under anoxic stress.
Main Methods:
- Isolation of a maize cDNA (CAP1) and its expression in yeast mutants lacking Ca2+-pumps.
- Biochemical assays to assess Ca2+ transport, Ca2+-dependent phosphorylation, and CaM binding.
- Immunological detection of the maize protein in microsomal fractions and its interaction with CaM.
Main Results:
- Maize CAP1 cDNA restored Ca2+-pump function and growth in yeast mutants.
- The expressed CAP1 protein integrated into yeast membranes, forming a phosphorylated intermediate and transporting Ca2+.
- CAP1 exhibited CaM-binding properties and CaM-stimulated Ca2+ transport, suggesting it's a CaM-regulated pump. CAP1 RNA levels increased during early anoxia.
Conclusions:
- CAP1 encodes a novel, calmodulin-regulated Ca2+-ATPase in maize.
- This Ca2+-ATPase plays a significant role in maize cells experiencing oxygen deprivation.
- CAP1 represents a new class of Ca2+-regulated pumps with potential implications for plant stress response.
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