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Gene Review

HA2  -  H(+)-ATPase 2

Arabidopsis thaliana

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High impact information on AHA2

  • Using the yeast two-hybrid system, we could show a direct interaction between Arabidopsis 14-3-3 GF14-phi and the last 98 C-terminal amino acids of the Arabidopsis AHA2 plasma membrane H(+)-ATPase [1].
  • All AHA2 species were correctly targeted to the yeast plasma membrane and, in addition, accumulated in internal membranes [2].
  • We observed that phosphorylation of AHA2 in the heterologous host and subsequent binding of 14-3-3 protein is crucial for the ability of AHA2 to substitute for Pma1 [3].
  • Thus, mutants of AHA2, complementing pma1, showed increased phosphorylation at the penultimate residue (Thr(947)), which creates a binding site for endogenous 14-3-3 protein [3].
  • To investigate the mechanism of ion transport by P-type ATPases we have mutagenized Asp(684), a residue in transmembrane segment M6 of AHA2 that is conserved in Ca(2+)-, Na(+)/K(+)-, H(+)/K(+)-, and H(+)-ATPases and which coordinates Ca(2+) ions in the SERCA1 Ca(2+)-ATPase [4].

Biological context of AHA2

  • In comparison with the 16 introns reported in AHA3, AHA2 is missing one intron in the 5'-untranslated region and a second intron in the C-terminal coding region [5].
  • We conclude that the extreme end of AHA2 contains an unusual high-affinity binding site for 14-3-3 protein [6].
  • Binding of 14-3-3 protein to the plasma membrane H(+)-ATPase AHA2 involves the three C-terminal residues Tyr(946)-Thr-Val and requires phosphorylation of Thr(947) [6].
  • ATP hydrolytic activity of AHA2 expressed in yeast internal membranes was activated by all tested isoforms of the 14-3-3 protein of yeast and Arabidopsis, but only in the presence of fusicoccin, and activation was prevented by a phosphoserine peptide representing a known 14-3-3 protein binding motif in Raf-1 [7].
  • When compared with AHA3, AHA1 and AHA2 had an apparent higher turnover rate for ATP hydrolysis, exhibited a 10-fold higher apparent affinity for ATP, and a 3-fold higher sensitivity toward vanadate [8].

Anatomical context of AHA2

  • By testing the fusicoccin binding activity of yeast membranes, the C-terminal regulatory domain of AHA2 was found to be part of a functional fusicoccin receptor, a component of which was the 14-3-3 protein [7].
  • AHA2 was expressed mainly in intracellular membranes and only supported very slow growth of transformed yeast cells [9].
  • We have used the 2.6 A structure of the rabbit sarcoplasmic reticulum Ca(2+)-ATPase isoform 1a, SERCA1a [Toyoshima, C., Nakasako, M., Nomura, H. and Ogawa, H. (2000) Nature 405, 647-655], to build models by homology modelling of two plasma membrane (PM) H(+)-ATPases, Arabidopsis thaliana AHA2 and Saccharomyces cerevisiae PMA1 [10].

Associations of AHA2 with chemical compounds


Other interactions of AHA2

  • The AHA2 gene is most similar to AHA1, with predicted proteins containing 95% amino acid identity [5].

Analytical, diagnostic and therapeutic context of AHA2

  • Northern blot analysis indicates that AHA2 mRNA relative to total cellular RNA is expressed at significantly higher levels in root tissue as compared with shoot tissue [5].
  • The mRNA start site and 5'-untranslated sequence for AHA2 were determined from cDNA amplified by the polymerase chain reaction [5].
  • Following site-directed mutagenesis within the 45 C-terminal residues of AHA2, we conclude that, in addition to the 946YpTV motif, a number of residues located further upstream are required for phosphorylation-independent binding of 14-3-3 [12].
  • Molecular dissection of the C-terminal regulatory domain of the plant plasma membrane H+-ATPase AHA2: mapping of residues that when altered give rise to an activated enzyme [11].


  1. The 14-3-3 protein interacts directly with the C-terminal region of the plant plasma membrane H(+)-ATPase. Jahn, T., Fuglsang, A.T., Olsson, A., Brüntrup, I.M., Collinge, D.B., Volkmann, D., Sommarin, M., Palmgren, M.G., Larsson, C. Plant Cell (1997) [Pubmed]
  2. C-terminal deletion analysis of plant plasma membrane H(+)-ATPase: yeast as a model system for solute transport across the plant plasma membrane. Regenberg, B., Villalba, J.M., Lanfermeijer, F.C., Palmgren, M.G. Plant Cell (1995) [Pubmed]
  3. Post-translational modification of plant plasma membrane H(+)-ATPase as a requirement for functional complementation of a yeast transport mutant. Jahn, T.P., Schulz, A., Taipalensuu, J., Palmgren, M.G. J. Biol. Chem. (2002) [Pubmed]
  4. Abolishment of proton pumping and accumulation in the E1P conformational state of a plant plasma membrane H+-ATPase by substitution of a conserved aspartyl residue in transmembrane segment 6. Buch-Pedersen, M.J., Venema, K., Serrano, R., Palmgren, M.G. J. Biol. Chem. (2000) [Pubmed]
  5. The Arabidopsis thaliana plasma membrane H(+)-ATPase multigene family. Genomic sequence and expression of a third isoform. Harper, J.F., Manney, L., DeWitt, N.D., Yoo, M.H., Sussman, M.R. J. Biol. Chem. (1990) [Pubmed]
  6. Binding of 14-3-3 protein to the plasma membrane H(+)-ATPase AHA2 involves the three C-terminal residues Tyr(946)-Thr-Val and requires phosphorylation of Thr(947). Fuglsang, A.T., Visconti, S., Drumm, K., Jahn, T., Stensballe, A., Mattei, B., Jensen, O.N., Aducci, P., Palmgren, M.G. J. Biol. Chem. (1999) [Pubmed]
  7. The 14-3-3 proteins associate with the plant plasma membrane H(+)-ATPase to generate a fusicoccin binding complex and a fusicoccin responsive system. Baunsgaard, L., Fuglsang, A.T., Jahn, T., Korthout, H.A., de Boer, A.H., Palmgren, M.G. Plant J. (1998) [Pubmed]
  8. Functional comparisons between plant plasma membrane H(+)-ATPase isoforms expressed in yeast. Palmgren, M.G., Christensen, G. J. Biol. Chem. (1994) [Pubmed]
  9. Complementation in situ of the yeast plasma membrane H(+)-ATPase gene pma1 by an H(+)-ATPase gene from a heterologous species. Palmgren, M.G., Christensen, G. FEBS Lett. (1993) [Pubmed]
  10. A putative proton binding site of plasma membrane H(+)-ATPase identified through homology modelling. Bukrinsky, J.T., Buch-Pedersen, M.J., Larsen, S., Palmgren, M.G. FEBS Lett. (2001) [Pubmed]
  11. Molecular dissection of the C-terminal regulatory domain of the plant plasma membrane H+-ATPase AHA2: mapping of residues that when altered give rise to an activated enzyme. Axelsen, K.B., Venema, K., Jahn, T., Baunsgaard, L., Palmgren, M.G. Biochemistry (1999) [Pubmed]
  12. The binding site for regulatory 14-3-3 protein in plant plasma membrane H+-ATPase: involvement of a region promoting phosphorylation-independent interaction in addition to the phosphorylation-dependent C-terminal end. Fuglsang, A.T., Borch, J., Bych, K., Jahn, T.P., Roepstorff, P., Palmgren, M.G. J. Biol. Chem. (2003) [Pubmed]
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