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Exploring the Potential Roles of Band 3 and Aquaporin-1 in Blood CO(2) Transport–Inspired by Comparative Studies of Glycophorin B-A-B Hybrid Protein GP.Mur
The Cl(—)/HCO(3)(—) exchanger band 3 is functionally relevant to blood CO(2) transport. Band 3 is the most abundant membrane protein in human red blood cells (RBCs). Our understanding of its physiological functions mainly came from clinical cases associated with band 3 mutations. Severe reduction in...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Frontiers Media S.A.
2018
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6018491/ https://www.ncbi.nlm.nih.gov/pubmed/29971013 http://dx.doi.org/10.3389/fphys.2018.00733 |
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author | Hsu, Kate |
author_facet | Hsu, Kate |
author_sort | Hsu, Kate |
collection | PubMed |
description | The Cl(—)/HCO(3)(—) exchanger band 3 is functionally relevant to blood CO(2) transport. Band 3 is the most abundant membrane protein in human red blood cells (RBCs). Our understanding of its physiological functions mainly came from clinical cases associated with band 3 mutations. Severe reduction in band 3 expression affects blood HCO(3)(—)/CO(2) metabolism. What could happen physiologically if band 3 expression is elevated instead? In some areas of Southeast Asia, about 1–10% of the populations express GP.Mur, a glycophorin B-A-B hybrid membrane protein important in the field of transfusion medicine. GP.Mur functions to promote band 3 expression, and GP.Mur red cells can be deemed as a naturally occurred model for higher band 3 expression. This review first compares the functional consequences of band 3 at different levels, and suggests a critical role of band 3 in postnatal CO(2) respiration. The second part of the review explores the transport of water, which is the other substrate for intra-erythrocytic CO(2)/HCO(3)(—) conversion (an essential step in blood CO(2) transport). Despite that water is considered unlimited physiologically, it is unclear whether water channel aquaporin-1 (AQP1) abundantly expressed in RBCs is functionally involved in CO(2) transport. Research in this area is complicated by the fact that the H(2)O/CO(2)-transporting function of AQP1 is replaceable by other erythrocyte channels/transporters (e.g., UT-B/GLUT1 for H(2)O; RhAG for CO(2)). Recently, using carbonic anhydrase II (CAII)-filled erythrocyte vesicles, AQP1 has been demonstrated to transport water for the CAII-mediated reaction, CO(2(g)) + H(2)O ⇌ HCO(3)(—)((aq)) + H(+)((aq)). AQP1 is structurally associated with some population of band 3 complexes on the erythrocyte membrane in an osmotically responsive fashion. The current findings reveal transient interaction among components within the band 3-central, CO(2)-transport metabolon (AQP1, band 3, CAII and deoxygenated hemoglobin). Their dynamic interaction is envisioned to facilitate blood CO(2) respiration, in the presence of constantly changing osmotic and hemodynamic stresses during circulation. |
format | Online Article Text |
id | pubmed-6018491 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-60184912018-07-03 Exploring the Potential Roles of Band 3 and Aquaporin-1 in Blood CO(2) Transport–Inspired by Comparative Studies of Glycophorin B-A-B Hybrid Protein GP.Mur Hsu, Kate Front Physiol Physiology The Cl(—)/HCO(3)(—) exchanger band 3 is functionally relevant to blood CO(2) transport. Band 3 is the most abundant membrane protein in human red blood cells (RBCs). Our understanding of its physiological functions mainly came from clinical cases associated with band 3 mutations. Severe reduction in band 3 expression affects blood HCO(3)(—)/CO(2) metabolism. What could happen physiologically if band 3 expression is elevated instead? In some areas of Southeast Asia, about 1–10% of the populations express GP.Mur, a glycophorin B-A-B hybrid membrane protein important in the field of transfusion medicine. GP.Mur functions to promote band 3 expression, and GP.Mur red cells can be deemed as a naturally occurred model for higher band 3 expression. This review first compares the functional consequences of band 3 at different levels, and suggests a critical role of band 3 in postnatal CO(2) respiration. The second part of the review explores the transport of water, which is the other substrate for intra-erythrocytic CO(2)/HCO(3)(—) conversion (an essential step in blood CO(2) transport). Despite that water is considered unlimited physiologically, it is unclear whether water channel aquaporin-1 (AQP1) abundantly expressed in RBCs is functionally involved in CO(2) transport. Research in this area is complicated by the fact that the H(2)O/CO(2)-transporting function of AQP1 is replaceable by other erythrocyte channels/transporters (e.g., UT-B/GLUT1 for H(2)O; RhAG for CO(2)). Recently, using carbonic anhydrase II (CAII)-filled erythrocyte vesicles, AQP1 has been demonstrated to transport water for the CAII-mediated reaction, CO(2(g)) + H(2)O ⇌ HCO(3)(—)((aq)) + H(+)((aq)). AQP1 is structurally associated with some population of band 3 complexes on the erythrocyte membrane in an osmotically responsive fashion. The current findings reveal transient interaction among components within the band 3-central, CO(2)-transport metabolon (AQP1, band 3, CAII and deoxygenated hemoglobin). Their dynamic interaction is envisioned to facilitate blood CO(2) respiration, in the presence of constantly changing osmotic and hemodynamic stresses during circulation. Frontiers Media S.A. 2018-06-19 /pmc/articles/PMC6018491/ /pubmed/29971013 http://dx.doi.org/10.3389/fphys.2018.00733 Text en Copyright © 2018 Hsu. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Physiology Hsu, Kate Exploring the Potential Roles of Band 3 and Aquaporin-1 in Blood CO(2) Transport–Inspired by Comparative Studies of Glycophorin B-A-B Hybrid Protein GP.Mur |
title | Exploring the Potential Roles of Band 3 and Aquaporin-1 in Blood CO(2) Transport–Inspired by Comparative Studies of Glycophorin B-A-B Hybrid Protein GP.Mur |
title_full | Exploring the Potential Roles of Band 3 and Aquaporin-1 in Blood CO(2) Transport–Inspired by Comparative Studies of Glycophorin B-A-B Hybrid Protein GP.Mur |
title_fullStr | Exploring the Potential Roles of Band 3 and Aquaporin-1 in Blood CO(2) Transport–Inspired by Comparative Studies of Glycophorin B-A-B Hybrid Protein GP.Mur |
title_full_unstemmed | Exploring the Potential Roles of Band 3 and Aquaporin-1 in Blood CO(2) Transport–Inspired by Comparative Studies of Glycophorin B-A-B Hybrid Protein GP.Mur |
title_short | Exploring the Potential Roles of Band 3 and Aquaporin-1 in Blood CO(2) Transport–Inspired by Comparative Studies of Glycophorin B-A-B Hybrid Protein GP.Mur |
title_sort | exploring the potential roles of band 3 and aquaporin-1 in blood co(2) transport–inspired by comparative studies of glycophorin b-a-b hybrid protein gp.mur |
topic | Physiology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6018491/ https://www.ncbi.nlm.nih.gov/pubmed/29971013 http://dx.doi.org/10.3389/fphys.2018.00733 |
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