Millls, R.F., Francini, A., Ferreira da Rocha, P.S.C., Baccarini, P.J., Aylett, M., Krijger, G.C. and Williams, L.E.
The plant P1B-type ATPase AtHMA4 transports Zn and Cd and plays a role in detoxification of transition metals supplied at elevated levels.
FEBS Letters, 579, (3), . (doi:10.1016/j.febslet.2004.12.040).
The transition metal Zn is essential for many physiological
processes in plants, yet at elevated concentrations this,
and the related non-essential metal Cd, can be toxic. Arabidopsis
thaliana HMA4, belonging to the Type P1B subfamily of P-type
ATPases, has recently been implicated in Zn nutrition, having a
role in root to shoot Zn translocation. Using Arabidopsis insertional
mutants, it is shown here that disruption of AtHMA4
function also results in increased sensitivity to elevated levels
of Cd and Zn, suggesting that AtHMA4 serves an important role
in metal detoxification at higher metal concentrations. AtHMA4
and a truncated form lacking the last 457 amino acids both confer
Cd and Zn resistance to yeast but a mutant version of the
full-length AtHMA4 (AtHMA4-C357G) does not; this demonstrates
that the C-terminal region is not essential for this function.
Evidence is presented that AtHMA4 functions as an
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