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Adaptable interaction between aquaporin‐1 and band 3 reveals a potential role of water channel in blood CO 2 transport
Author(s) -
Hsu Kate,
Lee TingYing,
Periasamy Ammasi,
Kao FuJen,
Li LiTzu,
Lin ChuangYu,
Lin HuiJu,
Lin Marie
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.201601282r
Subject(s) - aquaporin , chemistry , band 3 , biophysics , förster resonance energy transfer , water transport , aquaporin 1 , hemoglobin , membrane , membrane potential , analytical chemistry (journal) , fluorescence , water channel , biochemistry , physics , membrane protein , biology , chromatography , water flow , quantum mechanics , environmental engineering , engineering , mechanical engineering , inlet
Human CO 2 respiration requires rapid conversion between CO 2 and HCO 3 − . Carbonic anhydrase II facilitates this reversible reaction inside red blood cells, and band 3 [anion exchanger 1 (AE1)] provides a passage for HCO 3 − flux across the cell membrane. These 2 proteins are core components of the CO 2 transport metabolon. Intracellular H 2 O is necessary for CO 2 /HCO 3 − conversion. However, abundantly expressed aquaporin 1 (AQP1) in erythrocytes is thought not to be part of band 3 complexes or the CO 2 transport metabolon. To solve this conundrum, we used Förster resonance energy transfer (FRET) measured by fluorescence lifetime imaging (FLIM‐FRET) and identified interaction between aquaporin‐1 and band 3 at a distance of 8 nm, within the range of dipole‐dipole interaction. Notably, their interaction was adaptable to membrane tonicity changes. This suggests that the function of AQP1 in tonicity response could be coupled or correlated to its function in band 3‐mediated CO 2 /HCO 3 − exchange. By demonstrating AQP1 as a mobile component of the CO 2 transport metabolon, our results uncover a potential role of water channel in blood CO 2 transport and respiration.—Hsu, K., Lee, T.‐Y., Periasamy, A., Kao, F.‐J., Li, L.‐T., Lin, C.‐Y., Lin, H.‐J., Lin, M. Adaptable interaction between aquaporin‐1 and band 3 reveals a potential role of water channel in blood CO 2 transport. FASEB J. 31, 4256–4264 (2017). www.fasebj.org