Type IIB Ca2+-ATPases have a terminal auto-inhibitory, domain the action of which is suppressed by calmodulin (CaM) binding. Here, we show that a peptide (6His-1M-I116) corresponding to the first 116 aminoacids (aa) of At-ACA8, the first cloned isoform of Arabidopsis thaliana plasma membrane Ca2+-ATPase, inhibits the activity of the enzyme deprived of the N-terminus by controlled trypsin treatment 10-fold more efficiently than a peptide (41I-T63) corresponding only to the CaM-binding site. A peptide (268E-W348) corresponding to 81 aa of the small cytoplasmic loop of At-ACA8 binds peptide 6His- 1M-I116 immobilized on Ni-NTA agarose. Peptide 268E-W348 stimulates Ca2+-ATPase activity. Its effect is not additive with that of CaM and is suppressed by tryptic cleavage of the N-terminus. These results provide the first functional identification of a site of intramolecular interaction with the terminal auto-inhibitory domain of type IIB Ca2+-ATPases. © 2004 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.
Luoni, L., Meneghelli, S., Bonza, M. C., & DeMichelis, M. I. (2004). Auto-inhibition of Arabidopsis thaliana plasma membrane Ca 2+-ATPase involves an interaction of the N-terminus with the small cytoplasmic loop. FEBS Letters, 574(1–3), 20–24. https://doi.org/10.1016/j.febslet.2004.08.003