Back to Search
Start Over
Dual mechanism of activation of plant plasma membrane Ca2+-ATPase by acidic phospholipids: evidence for a phospholipid binding site which overlaps the calmodulin-binding site.
- Source :
-
Molecular membrane biology [Mol Membr Biol] 2008 Sep; Vol. 25 (6-7), pp. 539-46. - Publication Year :
- 2008
-
Abstract
- The effect of phospholipids on the activity of isoform ACA8 of Arabidopsis thaliana plasma membrane (PM) Ca2+-ATPase was evaluated in membranes isolated from Saccharomyces cerevisiae strain K616 expressing wild type or mutated ACA8 cDNA. Acidic phospholipids stimulated the basal Ca2+-ATPase activity in the following order of efficiency: phosphatidylinositol 4-monophosphate > phosphatidylserine > phosphatidylcholine approximately = phosphatidylethanolamine approximately = 0. Acidic phospholipids increased V(max-Ca2+) and lowered the value of K(0.5-Ca2+) below the value measured in the presence of calmodulin (CaM). In the presence of CaM acidic phospholipids activated ACA8 by further decreasing its K(0.5-Ca2+) value. Phosphatidylinositol 4-monophosphate and, with lower efficiency, phosphatidylserine bound peptides reproducing ACA8 N-terminus (aa 1-116). Single point mutation of three residues (A56, R59 and Y62) within the sequence A56-T63 lowered the apparent affinity of ACA8 for phosphatidylinositol 4-monophosphate by two to three fold, indicating that this region contains a binding site for acidic phospholipids. However, the N-deleted mutant Delta74-ACA8 was also activated by acidic phospholipids, indicating that acidic phospholipids activate ACA8 through a complex mechanism, involving interaction with different sites. The striking similarity between the response to acidic phospholipids of ACA8 and animal plasma membrane Ca2+-ATPase provides new evidence that type 2B Ca2+-ATPases share common regulatory properties independently of structural differences such as the localization of the terminal regulatory region at the N- or C-terminal end of the protein.
- Subjects :
- Arabidopsis Proteins genetics
Binding Sites
Calcium-Transporting ATPases genetics
Calmodulin metabolism
Enzyme Activation
Membrane Proteins
Mutation
Phospholipids pharmacology
Protein Isoforms
Saccharomyces cerevisiae genetics
Arabidopsis enzymology
Arabidopsis Proteins metabolism
Calcium-Transporting ATPases metabolism
Phospholipids metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1464-5203
- Volume :
- 25
- Issue :
- 6-7
- Database :
- MEDLINE
- Journal :
- Molecular membrane biology
- Publication Type :
- Academic Journal
- Accession number :
- 18988067
- Full Text :
- https://doi.org/10.1080/09687680802508747