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Molecular and biochemical properties of two P 1B2 ‐ ATPases , CsHMA 3 and CsHMA 4, from cucumber
Author(s) -
MIGOCKA MAGDALENA,
PAPIERNIAK ANNA,
MACIASZCZYKDZIUBINSKA EWA,
POSYNIAK EWELINA,
KOSIERADZKA ANNA
Publication year - 2015
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12447
Subject(s) - yeast , saccharomyces cerevisiae , biology , biochemistry , chemistry
P 1B ‐ ATPases (heavy metal ATPases , HMA s) constitute a multigenic subfamily of P ‐ ATPases involved in the transport of monovalent and divalent heavy metals in plant cells. Here, we present the organization of genes encoding the HMA family in the cucumber genome and report the function and biochemical properties of two cucumber proteins homologous to the HMA 2‐4‐like plant HMA s. Eight genes encoding putative P 1B ‐ ATPases were identified in the cucumber genome. Among them, CsHMA3 was predominantly expressed in roots and up‐regulated by Pb , Zn and Cd excess, whereas the CsHMA4 transcript was most abundant in roots and flowers of cucumber plants, and elevated under Pb and Zn excess. Expression of CsHMA3 in S accharomyces cerevisiae enhanced yeast tolerance to Cd and Pb , whereas CsHMA4 conferred increased resistance of yeast cells to Cd and Zn . Immunostaining with specific antibodies raised against cucumber proteins revealed tonoplast localization of CsHMA 3 and plasma membrane localization of CsHMA 4 in cucumber root cells. Kinetic studies of CsHMA 3 and CsHMA 4 in yeast membranes indicated differing heavy metal cation affinities of these two proteins. Altogether, the results suggest an important role of CsHMA 3 and CsHMA 4 in Cd and Pb detoxification and Zn homeostasis in cucumber cells.