Format

Send to

Choose Destination
Plant Cell Physiol. 2014 Feb;55(2):251-7. doi: 10.1093/pcp/pcu003. Epub 2014 Jan 8.

CO2 transport by PIP2 aquaporins of barley.

Author information

1
Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki, 710-0046 Japan.

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.

KEYWORDS:

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

PMID:
24406630
PMCID:
PMC3913445
DOI:
10.1093/pcp/pcu003
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center