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 journalArticle

42 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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    Mori, I. C., Rhee, J., Shibasaka, M., Sasano, S., Kaneko, T., Horie, T., & Katsuhara, M. (2014). CO2 transport by PIP2 aquaporins of barley. Plant and Cell Physiology, 55(2), 251-257. https://doi.org/10.1093/pcp/pcu003