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Updated: Jun 26, 2026

A New Approach for the Comparative Analysis of Multiprotein Complexes Based on 15N Metabolic Labeling and Quantitative Mass Spectrometry
Published on: March 13, 2014
The primary identification of a calcineurin A subunit-like protein in plants
Chenggang Yang1, Hongtao Song, Hua Weng
1Department of Biochemistry and Molecular Biology, Beijing Normal University, Beijing Key Laboratory, Beijing 100875, China.
Abstract:
Many types of serine/threonine protein phosphatase have been cloned and characterized in plants, such as Type-1 serine/threonine protein phosphatase (PP1), Type-2A serine/threonine protein phosphatase (PP2A), Type-2C serine/threonine protein phosphatase (PP2C). However no Type-2B serine/threonine protein phosphatase (PP2B, calcineurin), or calcineurin A subunit-like protein (CaNAL), has been identified. We detected protein phosphatase activity in mixtures of CaM-binding proteins from three plants (Nicotiana tabacum, Brassica oleracea and Arabidopsis thaliana). Two-dimensional electrophoresis (2-D) and Western blot analysis with an anti-rat CNA antibody revealed a small protein of 60 kDa that we believe is a CaNAL. The isoelectric point (pI) of this protein in N. tabacum was approximately 5.69. The protein phosphatase activity in the mixture of CaM-binding proteins from N. tabacum was regulated by Ca(2+) and Calmodulin (CaM) with either RII peptides or pNPP as substrate. The immunosuppressive drugs, CsA and FK506, also inhibited the protein phosphatase activity significantly.
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