Electrophysiological study of Arabidopsis ABCB4 and PIN2 auxin transporters: Evidence of auxin activation and interaction enhancing auxin selectivity

Abstract Polar auxin transport through plant tissue strictly requires polarly localized PIN proteins and uniformly distributed ABCB proteins. A functional synergy between the two types of membrane protein where their localizations overlap may create the degree of asymmetric auxin efflux required to...

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Autores principales:	Stephen D. Deslauriers, Edgar P. Spalding
Formato:	article
Lenguaje:	EN
Publicado:	Wiley 2021
Materias:	Botany QK1-989
Acceso en línea:	https://doaj.org/article/e54e7e895e754d3c93f7176177416ffc
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spelling	oai:doaj.org-article:e54e7e895e754d3c93f7176177416ffc2021-11-29T07:25:55ZElectrophysiological study of Arabidopsis ABCB4 and PIN2 auxin transporters: Evidence of auxin activation and interaction enhancing auxin selectivity2475-445510.1002/pld3.361https://doaj.org/article/e54e7e895e754d3c93f7176177416ffc2021-11-01T00:00:00Zhttps://doi.org/10.1002/pld3.361https://doaj.org/toc/2475-4455Abstract Polar auxin transport through plant tissue strictly requires polarly localized PIN proteins and uniformly distributed ABCB proteins. A functional synergy between the two types of membrane protein where their localizations overlap may create the degree of asymmetric auxin efflux required to produce polar auxin transport. We investigated this possibility by expressing ABCB4 and PIN2 in human embryonic kidney cells and measuring whole‐cell ionic currents with the patch‐clamp technique and CsCl‐based electrolytes. ABCB4 activity was 1.81‐fold more selective for Cl− over Cs+ and for PIN2 the value was 2.95. We imposed auxin gradients and determined that ABCB4 and PIN2 were 12‐fold more permeable to the auxin anion (IAA−) than Cl−. This measure of the intrinsic selectivity of the transport pathway was 21‐fold when ABCB4 and PIN2 were co‐expressed. If this increase occurs in plants, it could explain why asymmetric PIN localization is not sufficient to create polar auxin flow. Some form of co‐action or synergy between ABCB4 and PIN2 that increases IAA− selectivity at the cell face where both occur may be important. We also found that auxin stimulated ABCB4 activity, which may contribute to a self‐reinforcement of auxin transport known as canalization.Stephen D. DeslauriersEdgar P. SpaldingWileyarticleBotanyQK1-989ENPlant Direct, Vol 5, Iss 11, Pp n/a-n/a (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Botany QK1-989
spellingShingle	Botany QK1-989 Stephen D. Deslauriers Edgar P. Spalding Electrophysiological study of Arabidopsis ABCB4 and PIN2 auxin transporters: Evidence of auxin activation and interaction enhancing auxin selectivity
description	Abstract Polar auxin transport through plant tissue strictly requires polarly localized PIN proteins and uniformly distributed ABCB proteins. A functional synergy between the two types of membrane protein where their localizations overlap may create the degree of asymmetric auxin efflux required to produce polar auxin transport. We investigated this possibility by expressing ABCB4 and PIN2 in human embryonic kidney cells and measuring whole‐cell ionic currents with the patch‐clamp technique and CsCl‐based electrolytes. ABCB4 activity was 1.81‐fold more selective for Cl− over Cs+ and for PIN2 the value was 2.95. We imposed auxin gradients and determined that ABCB4 and PIN2 were 12‐fold more permeable to the auxin anion (IAA−) than Cl−. This measure of the intrinsic selectivity of the transport pathway was 21‐fold when ABCB4 and PIN2 were co‐expressed. If this increase occurs in plants, it could explain why asymmetric PIN localization is not sufficient to create polar auxin flow. Some form of co‐action or synergy between ABCB4 and PIN2 that increases IAA− selectivity at the cell face where both occur may be important. We also found that auxin stimulated ABCB4 activity, which may contribute to a self‐reinforcement of auxin transport known as canalization.
format	article
author	Stephen D. Deslauriers Edgar P. Spalding
author_facet	Stephen D. Deslauriers Edgar P. Spalding
author_sort	Stephen D. Deslauriers
title	Electrophysiological study of Arabidopsis ABCB4 and PIN2 auxin transporters: Evidence of auxin activation and interaction enhancing auxin selectivity
title_short	Electrophysiological study of Arabidopsis ABCB4 and PIN2 auxin transporters: Evidence of auxin activation and interaction enhancing auxin selectivity
title_full	Electrophysiological study of Arabidopsis ABCB4 and PIN2 auxin transporters: Evidence of auxin activation and interaction enhancing auxin selectivity
title_fullStr	Electrophysiological study of Arabidopsis ABCB4 and PIN2 auxin transporters: Evidence of auxin activation and interaction enhancing auxin selectivity
title_full_unstemmed	Electrophysiological study of Arabidopsis ABCB4 and PIN2 auxin transporters: Evidence of auxin activation and interaction enhancing auxin selectivity
title_sort	electrophysiological study of arabidopsis abcb4 and pin2 auxin transporters: evidence of auxin activation and interaction enhancing auxin selectivity
publisher	Wiley
publishDate	2021
url	https://doaj.org/article/e54e7e895e754d3c93f7176177416ffc
work_keys_str_mv	AT stephenddeslauriers electrophysiologicalstudyofarabidopsisabcb4andpin2auxintransportersevidenceofauxinactivationandinteractionenhancingauxinselectivity AT edgarpspalding electrophysiologicalstudyofarabidopsisabcb4andpin2auxintransportersevidenceofauxinactivationandinteractionenhancingauxinselectivity
_version_	1718407557726339072

Electrophysiological study of Arabidopsis ABCB4 and PIN2 auxin transporters: Evidence of auxin activation and interaction enhancing auxin selectivity

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