CO2 transport by PIP2 aquaporins of barley

Izumi C. Mori, Jiye Rhee, Mineo Shibasaka, Shizuka Sasano, Toshiyuki Kaneko, Tomoaki Horie, Maki Katsuhara

    Research output: Contribution to journalArticlepeer-review

    50 Citations (Scopus)

    Abstract

    CO2 permeability of plasma membrane intrinsic protein 2 (PIP2) aquaporins of Hordeum vulgare L. was investigated. Five PIP2 members were heterologously expressed in Xenopus laevis oocytes. CO2 permeability was determined by decrease of cytosolic pH in CO2-enriched buffer using a hydrogen ion-selective microelectrode. HvPIP2;1, HvPIP2;2, HvPIP2;3 and HvPIP2;5 facilitated CO2 transport across the oocyte cell membrane. However, HvPIP2;4 that is highly homologous to HvPIP2;3 did not. The isoleucine residue at position 254 of HvPIP2;3 was conserved in PIP2 aquaporins of barley, except HvPIP2;4, which possesses methionine instead. CO2 permeability was lost by the substitution of the Ile254 of HvPIP2;3 by methionine, while water permeability was not affected. These results suggest that PIP2 aquaporins are permeable to CO2. and the conserved isoleucine at the end of the E-loop is crucial for CO2 selectivity.

    Original languageEnglish
    Pages (from-to)251-257
    Number of pages7
    JournalPlant and Cell Physiology
    Volume55
    Issue number2
    DOIs
    Publication statusPublished - Feb 2014

    Keywords

    • Aquaporin
    • Barley
    • Carbon dioxide
    • Plasma membrane intrinsic protein 2

    ASJC Scopus subject areas

    • Physiology
    • Plant Science
    • Cell Biology

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