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The plant plasma membrane Ca2+ pump ACA8 contains overlapping as well as physically separated autoinhibitory and calmodulin-binding domains.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2006 Jan 13; Vol. 281 (2), pp. 1058-65. Date of Electronic Publication: 2005 Nov 01. - Publication Year :
- 2006
-
Abstract
- In plant Ca(2+) pumps belonging to the P(2B) subfamily of P-type ATPases, the N-terminal cytoplasmic domain is responsible for pump autoinhibition. Binding of calmodulin (CaM) to this region results in pump activation but the structural basis for CaM activation is still not clear. All residues in a putative CaM-binding domain (Arg(43) to Lys(68)) were mutagenized and the resulting recombinant proteins were studied with respect to CaM binding and the activation state. The results demonstrate that (i) the binding site for CaM is overlapping with the autoinhibitory region and (ii) the autoinhibitory region comprises significantly fewer residues than the CaM-binding region. In a helical wheel projection of the CaM-binding domain, residues involved in autoinhibition cluster on one side of the helix, which is proposed to interact with an intramolecular receptor site in the pump. Residues influencing CaM negatively are situated on the other face of the helix, likely to face the cytosol, whereas residues controlling CaM binding positively are scattered throughout. We propose that early CaM recognition is mediated by the cytosolic face and that CaM subsequently competes with the intramolecular autoinhibitor in binding to the other face of the helix.
- Subjects :
- Adenosine Triphosphatases chemistry
Adenosine Triphosphate chemistry
Amino Acid Motifs
Amino Acid Sequence
Animals
Arabidopsis Proteins physiology
Arginine chemistry
Biotinylation
Calcium chemistry
Calcium metabolism
Calcium-Transporting ATPases metabolism
Calcium-Transporting ATPases physiology
Cattle
Cytosol metabolism
Genetic Complementation Test
Green Fluorescent Proteins chemistry
Green Fluorescent Proteins metabolism
Hydrolysis
Kinetics
Lysine chemistry
Molecular Sequence Data
Muscle, Skeletal enzymology
Mutagenesis, Site-Directed
Mutation
Plasmids metabolism
Protein Binding
Protein Conformation
Protein Structure, Tertiary
Saccharomyces cerevisiae metabolism
Surface Plasmon Resonance
Time Factors
Arabidopsis metabolism
Arabidopsis Proteins chemistry
Calcium-Transporting ATPases chemistry
Calmodulin chemistry
Cell Membrane metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 281
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 16267044
- Full Text :
- https://doi.org/10.1074/jbc.M508299200