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Nat Commun. 2018 Jul 18;9(1):2809. doi: 10.1038/s41467-018-05253-x.

The solute carrier SLC9C1 is a Na+/H+-exchanger gated by an S4-type voltage-sensor and cyclic-nucleotide binding.

Author information

1
Center of Advanced European Studies and Research (caesar), Department Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany.
2
Marine Biological Laboratory, 7 MBL Street, Woods Hole, 02543, MA, USA.
3
University Hospital Münster, Center of Reproductive Medicine and Andrology, Albert-Schweitzer-Campus 1, Geb. D11, 48149, Münster, Germany.
4
Center of Advanced European Studies and Research (caesar), Department Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany. reinhard.seifert@caesar.de.
5
Marine Biological Laboratory, 7 MBL Street, Woods Hole, 02543, MA, USA. reinhard.seifert@caesar.de.
6
Center of Advanced European Studies and Research (caesar), Department Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany. u.b.kaupp@caesar.de.
7
Marine Biological Laboratory, 7 MBL Street, Woods Hole, 02543, MA, USA. u.b.kaupp@caesar.de.
8
University of Bonn, Life & Medical Sciences Institute (LIMES), Carl-Troll-Str. 31, 53115, Bonn, Germany. u.b.kaupp@caesar.de.

Abstract

Voltage-sensing (VSD) and cyclic nucleotide-binding domains (CNBD) gate ion channels for rapid electrical signaling. By contrast, solute carriers (SLCs) that passively redistribute substrates are gated by their substrates themselves. Here, we study the orphan sperm-specific solute carriers SLC9C1 that feature a unique tripartite structure: an exchanger domain, a VSD, and a CNBD. Voltage-clamp fluorimetry shows that SLC9C1 is a genuine Na+/H+ exchanger gated by voltage. The cellular messenger cAMP shifts the voltage range of activation. Mutations in the transport domain, the VSD, or the CNBD strongly affect Na+/H+ exchange, voltage gating, or cAMP sensitivity, respectively. Our results establish SLC9C1 as a phylogenetic chimaera that combines the ion-exchange mechanism of solute carriers with the gating mechanism of ion channels. Classic SLCs slowly readjust changes in the intra- and extracellular milieu, whereas voltage gating endows the Na+/H+ exchanger with the ability to produce a rapid pH response that enables downstream signaling events.

PMID:
30022052
PMCID:
PMC6052114
DOI:
10.1038/s41467-018-05253-x
[Indexed for MEDLINE]
Free PMC Article

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