Amino Acids 785, 787 of the Na+/H+ Exchanger Cytoplasmic Tail Modulate Protein Activity and Tail Conformation

The mammalian Na+/H+ exchanger isoform 1 (NHE1) is a plasma membrane protein ubiquitously present in humans. It regulates intracellular pH by removing an intracellular proton in exchange for an extracellular sodium. It consists of a 500 amino acid membra...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Xiuju Li, Tommy Tu, Sicheng Quan, Francisco J. Quintero, Richard Fahlman, Larry Fliegel
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	Na<sup>+</sup>/H<sup>+</sup> exchanger pH regulation phosphorylation intracellular pH membrane protein Biology (General) QH301-705.5 Chemistry QD1-999
Acceso en línea:	https://doaj.org/article/64a37761fd58401087492383dfd1d996
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:64a37761fd58401087492383dfd1d996
record_format	dspace
spelling	oai:doaj.org-article:64a37761fd58401087492383dfd1d9962021-11-11T16:49:38ZAmino Acids 785, 787 of the Na<sup>+</sup>/H<sup>+</sup> Exchanger Cytoplasmic Tail Modulate Protein Activity and Tail Conformation10.3390/ijms2221113491422-00671661-6596https://doaj.org/article/64a37761fd58401087492383dfd1d9962021-10-01T00:00:00Zhttps://www.mdpi.com/1422-0067/22/21/11349https://doaj.org/toc/1661-6596https://doaj.org/toc/1422-0067The mammalian Na<sup>+</sup>/H<sup>+</sup> exchanger isoform 1 (NHE1) is a plasma membrane protein ubiquitously present in humans. It regulates intracellular pH by removing an intracellular proton in exchange for an extracellular sodium. It consists of a 500 amino acid membrane domain plus a 315 amino acid, regulatory cytosolic tail. Here, we investigated the effect of mutation of two amino acids of the regulatory tail, Ser<sup>785</sup> and Ser<sup>787</sup>, that were similar in location and context to two amino acids of the <i>Arabidopsis</i> Na<sup>+</sup>/H<sup>+</sup> exchanger SOS1. Mutation of these two amino acids to either Ala or phosphomimetic Glu did not affect surface targeting but led to a slight reduction in the level of protein expressed. The activity of the NHE1 protein was reduced in the phosphomimetic mutations and the effect was due to a decrease in Vmax activity. The Ser to Glu mutations also caused a change in the apparent molecular weight of both the full-length protein and of the cytosolic tail of NHE1. A conformational change in this region was indicated by differential trypsin sensitivity. We also found that a peptide containing amino acids 783–790 bound to several more proximal regions of the NHE1 tail in in vitro protein interaction experiments. The results are the first characterization of these two amino acids and show that they have significant effects on enzyme kinetics and the structure of the NHE1 protein.Xiuju LiTommy TuSicheng QuanFrancisco J. QuinteroRichard FahlmanLarry FliegelMDPI AGarticleNa<sup>+</sup>/H<sup>+</sup> exchangerpH regulationphosphorylationintracellular pHmembrane proteinBiology (General)QH301-705.5ChemistryQD1-999ENInternational Journal of Molecular Sciences, Vol 22, Iss 11349, p 11349 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Na<sup>+</sup>/H<sup>+</sup> exchanger pH regulation phosphorylation intracellular pH membrane protein Biology (General) QH301-705.5 Chemistry QD1-999
spellingShingle	Na<sup>+</sup>/H<sup>+</sup> exchanger pH regulation phosphorylation intracellular pH membrane protein Biology (General) QH301-705.5 Chemistry QD1-999 Xiuju Li Tommy Tu Sicheng Quan Francisco J. Quintero Richard Fahlman Larry Fliegel Amino Acids 785, 787 of the Na<sup>+</sup>/H<sup>+</sup> Exchanger Cytoplasmic Tail Modulate Protein Activity and Tail Conformation
description	The mammalian Na<sup>+</sup>/H<sup>+</sup> exchanger isoform 1 (NHE1) is a plasma membrane protein ubiquitously present in humans. It regulates intracellular pH by removing an intracellular proton in exchange for an extracellular sodium. It consists of a 500 amino acid membrane domain plus a 315 amino acid, regulatory cytosolic tail. Here, we investigated the effect of mutation of two amino acids of the regulatory tail, Ser<sup>785</sup> and Ser<sup>787</sup>, that were similar in location and context to two amino acids of the <i>Arabidopsis</i> Na<sup>+</sup>/H<sup>+</sup> exchanger SOS1. Mutation of these two amino acids to either Ala or phosphomimetic Glu did not affect surface targeting but led to a slight reduction in the level of protein expressed. The activity of the NHE1 protein was reduced in the phosphomimetic mutations and the effect was due to a decrease in Vmax activity. The Ser to Glu mutations also caused a change in the apparent molecular weight of both the full-length protein and of the cytosolic tail of NHE1. A conformational change in this region was indicated by differential trypsin sensitivity. We also found that a peptide containing amino acids 783–790 bound to several more proximal regions of the NHE1 tail in in vitro protein interaction experiments. The results are the first characterization of these two amino acids and show that they have significant effects on enzyme kinetics and the structure of the NHE1 protein.
format	article
author	Xiuju Li Tommy Tu Sicheng Quan Francisco J. Quintero Richard Fahlman Larry Fliegel
author_facet	Xiuju Li Tommy Tu Sicheng Quan Francisco J. Quintero Richard Fahlman Larry Fliegel
author_sort	Xiuju Li
title	Amino Acids 785, 787 of the Na<sup>+</sup>/H<sup>+</sup> Exchanger Cytoplasmic Tail Modulate Protein Activity and Tail Conformation
title_short	Amino Acids 785, 787 of the Na<sup>+</sup>/H<sup>+</sup> Exchanger Cytoplasmic Tail Modulate Protein Activity and Tail Conformation
title_full	Amino Acids 785, 787 of the Na<sup>+</sup>/H<sup>+</sup> Exchanger Cytoplasmic Tail Modulate Protein Activity and Tail Conformation
title_fullStr	Amino Acids 785, 787 of the Na<sup>+</sup>/H<sup>+</sup> Exchanger Cytoplasmic Tail Modulate Protein Activity and Tail Conformation
title_full_unstemmed	Amino Acids 785, 787 of the Na<sup>+</sup>/H<sup>+</sup> Exchanger Cytoplasmic Tail Modulate Protein Activity and Tail Conformation
title_sort	amino acids 785, 787 of the na<sup>+</sup>/h<sup>+</sup> exchanger cytoplasmic tail modulate protein activity and tail conformation
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/64a37761fd58401087492383dfd1d996
work_keys_str_mv	AT xiujuli aminoacids785787ofthenasupsuphsupsupexchangercytoplasmictailmodulateproteinactivityandtailconformation AT tommytu aminoacids785787ofthenasupsuphsupsupexchangercytoplasmictailmodulateproteinactivityandtailconformation AT sichengquan aminoacids785787ofthenasupsuphsupsupexchangercytoplasmictailmodulateproteinactivityandtailconformation AT franciscojquintero aminoacids785787ofthenasupsuphsupsupexchangercytoplasmictailmodulateproteinactivityandtailconformation AT richardfahlman aminoacids785787ofthenasupsuphsupsupexchangercytoplasmictailmodulateproteinactivityandtailconformation AT larryfliegel aminoacids785787ofthenasupsuphsupsupexchangercytoplasmictailmodulateproteinactivityandtailconformation
_version_	1718432242900926464

Amino Acids 785, 787 of the Na<sup>+</sup>/H<sup>+</sup> Exchanger Cytoplasmic Tail Modulate Protein Activity and Tail Conformation

Ejemplares similares