Functional Cooperativity between ABCG4 and ABCG1 Isoforms.

ABCG4 belongs to the ABCG subfamily, the members of which are half transporters composed of a single transmembrane and a single nucleotide-binding domain. ABCG proteins have a reverse domain topology as compared to other mammalian ABC transporters, and have to form functional dimers, since the catal...

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Main Authors: Zoltán Hegyi, László Homolya
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2016-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC4882005?pdf=render
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author Zoltán Hegyi
László Homolya
author_facet Zoltán Hegyi
László Homolya
author_sort Zoltán Hegyi
collection DOAJ
description ABCG4 belongs to the ABCG subfamily, the members of which are half transporters composed of a single transmembrane and a single nucleotide-binding domain. ABCG proteins have a reverse domain topology as compared to other mammalian ABC transporters, and have to form functional dimers, since the catalytic sites for ATP binding and hydrolysis, as well as the transmembrane domains are composed of distinct parts of the monomers. Here we demonstrate that ABCG4 can form homodimers, but also heterodimers with its closest relative, ABCG1. Both the full-length and the short isoforms of ABCG1 can dimerize with ABCG4, whereas the ABCG2 multidrug transporter is unable to form a heterodimer with ABCG4. We also show that contrary to that reported in some previous studies, ABCG4 is predominantly localized to the plasma membrane. While both ABCG1 and ABCG4 have been suggested to be involved in lipid transport or regulation, in accordance with our previous results regarding the long version of ABCG1, here we document that the expression of both the short isoform of ABCG1 as well as ABCG4 induce apoptosis in various cell types. This apoptotic effect, as a functional read-out, allowed us to demonstrate that the dimerization between these half transporters is not only a physical interaction but functional cooperativity. Given that ABCG4 is predominantly expressed in microglial-like cells and endothelial cells in the brain, our finding of ABCG4-induced apoptosis may implicate a new role for this protein in the clearance mechanisms within the central nervous system.
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spelling doaj.art-3aef69ca96874d5186d65b56de534e902022-12-21T17:32:31ZengPublic Library of Science (PLoS)PLoS ONE1932-62032016-01-01115e015651610.1371/journal.pone.0156516Functional Cooperativity between ABCG4 and ABCG1 Isoforms.Zoltán HegyiLászló HomolyaABCG4 belongs to the ABCG subfamily, the members of which are half transporters composed of a single transmembrane and a single nucleotide-binding domain. ABCG proteins have a reverse domain topology as compared to other mammalian ABC transporters, and have to form functional dimers, since the catalytic sites for ATP binding and hydrolysis, as well as the transmembrane domains are composed of distinct parts of the monomers. Here we demonstrate that ABCG4 can form homodimers, but also heterodimers with its closest relative, ABCG1. Both the full-length and the short isoforms of ABCG1 can dimerize with ABCG4, whereas the ABCG2 multidrug transporter is unable to form a heterodimer with ABCG4. We also show that contrary to that reported in some previous studies, ABCG4 is predominantly localized to the plasma membrane. While both ABCG1 and ABCG4 have been suggested to be involved in lipid transport or regulation, in accordance with our previous results regarding the long version of ABCG1, here we document that the expression of both the short isoform of ABCG1 as well as ABCG4 induce apoptosis in various cell types. This apoptotic effect, as a functional read-out, allowed us to demonstrate that the dimerization between these half transporters is not only a physical interaction but functional cooperativity. Given that ABCG4 is predominantly expressed in microglial-like cells and endothelial cells in the brain, our finding of ABCG4-induced apoptosis may implicate a new role for this protein in the clearance mechanisms within the central nervous system.http://europepmc.org/articles/PMC4882005?pdf=render
spellingShingle Zoltán Hegyi
László Homolya
Functional Cooperativity between ABCG4 and ABCG1 Isoforms.
PLoS ONE
title Functional Cooperativity between ABCG4 and ABCG1 Isoforms.
title_full Functional Cooperativity between ABCG4 and ABCG1 Isoforms.
title_fullStr Functional Cooperativity between ABCG4 and ABCG1 Isoforms.
title_full_unstemmed Functional Cooperativity between ABCG4 and ABCG1 Isoforms.
title_short Functional Cooperativity between ABCG4 and ABCG1 Isoforms.
title_sort functional cooperativity between abcg4 and abcg1 isoforms
url http://europepmc.org/articles/PMC4882005?pdf=render
work_keys_str_mv AT zoltanhegyi functionalcooperativitybetweenabcg4andabcg1isoforms
AT laszlohomolya functionalcooperativitybetweenabcg4andabcg1isoforms