The Intracellular Distal Tail of the Na+/H+ Exchanger NHE1 Is Intrinsically Disordered: Implications for NHE1 Trafficking

Ann-Beth Nørholm; Ruth Hendus-Altenburger; Gabriel Bjerre; Magnus Kjærgaard; Stine Helene Falsig Pedersen; Birthe B Kragelund

doi:10.1021/bi1019989

The Intracellular Distal Tail of the Na⁺/H⁺ Exchanger NHE1 Is Intrinsically Disordered: Implications for NHE1 Trafficking

Ann-Beth Nørholm, Ruth Hendus-Altenburger, Gabriel Bjerre, Magnus Kjærgaard, Stine Helene Falsig Pedersen, Birthe B Kragelund

49 Citations (Scopus)

Abstract

Intrinsic disorder is important for protein regulation, yet its role in regulation of ion transport proteins is essentially uninvestigated. The ubiquitous plasma membrane carrier protein Na(+)/H(+) Exchanger isoform 1 (NHE1) plays pivotal roles in cellular pH and volume homeostasis, and its dysfunction is implicated in several clinically important diseases. This study shows, for the first time for any carrier protein, that the distal part of the C-terminal intracellular tail (the cdt, residues V686-Q815) from human (h) NHE1 is intrinsically disordered. Further, we experimentally demonstrated the presence of a similar region of intrinsic disorder (ID) in NHE1 from the teleost fish Pleuronectes americanus (paNHE1), and bioinformatic analysis suggested ID to be conserved in the NHE1 family. The sequential variation in structure propensity as determined by NMR, but not the amplitude, was largely conserved between the h- and paNHE1cdt. This suggests that both proteins contain molecular recognition features (MoRFs), i.e., local, transiently formed structures within an ID region. The functional relevance of the most conserved MoRF was investigated by introducing a point mutation that significantly disrupted the putative binding feature. When this mutant NHE1 was expressed in full length NHE1 in AP1 cells, it exhibited impaired trafficking to the plasma membrane. This study demonstrated that the distal regulatory domain of NHE1 is intrinsically disordered yet contains conserved regions of transient structure. We suggest that normal NHE1 function depends on a protein recognition element within the ID region that may be linked to NHE1 trafficking via an acidic ER export motif.

Original language	English
Journal	Biochemistry
Volume	50
Issue number	17
Pages (from-to)	3469-80
Number of pages	12
ISSN	1520-4995
DOIs	https://doi.org/10.1021/bi1019989
Publication status	Published - 3 May 2011

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1021/bi1019989

Cite this

@article{06a277eff2a94617ab0935afebe7e608,

title = "The Intracellular Distal Tail of the Na+/H+ Exchanger NHE1 Is Intrinsically Disordered: Implications for NHE1 Trafficking",

abstract = "Intrinsic disorder is important for protein regulation, yet its role in regulation of ion transport proteins is essentially uninvestigated. The ubiquitous plasma membrane carrier protein Na(+)/H(+) Exchanger isoform 1 (NHE1) plays pivotal roles in cellular pH and volume homeostasis, and its dysfunction is implicated in several clinically important diseases. This study shows, for the first time for any carrier protein, that the distal part of the C-terminal intracellular tail (the cdt, residues V686-Q815) from human (h) NHE1 is intrinsically disordered. Further, we experimentally demonstrated the presence of a similar region of intrinsic disorder (ID) in NHE1 from the teleost fish Pleuronectes americanus (paNHE1), and bioinformatic analysis suggested ID to be conserved in the NHE1 family. The sequential variation in structure propensity as determined by NMR, but not the amplitude, was largely conserved between the h- and paNHE1cdt. This suggests that both proteins contain molecular recognition features (MoRFs), i.e., local, transiently formed structures within an ID region. The functional relevance of the most conserved MoRF was investigated by introducing a point mutation that significantly disrupted the putative binding feature. When this mutant NHE1 was expressed in full length NHE1 in AP1 cells, it exhibited impaired trafficking to the plasma membrane. This study demonstrated that the distal regulatory domain of NHE1 is intrinsically disordered yet contains conserved regions of transient structure. We suggest that normal NHE1 function depends on a protein recognition element within the ID region that may be linked to NHE1 trafficking via an acidic ER export motif.",

author = "Ann-Beth N{\o}rholm and Ruth Hendus-Altenburger and Gabriel Bjerre and Magnus Kj{\ae}rgaard and Pedersen, {Stine Helene Falsig} and Kragelund, {Birthe B}",

year = "2011",

month = may,

day = "3",

doi = "10.1021/bi1019989",

language = "English",

volume = "50",

pages = "3469--80",

journal = "Biochemistry",

issn = "0006-2960",

publisher = "American Chemical Society",

number = "17",

}

TY - JOUR

T1 - The Intracellular Distal Tail of the Na+/H+ Exchanger NHE1 Is Intrinsically Disordered

T2 - Implications for NHE1 Trafficking

AU - Nørholm, Ann-Beth

AU - Hendus-Altenburger, Ruth

AU - Bjerre, Gabriel

AU - Kjærgaard, Magnus

AU - Pedersen, Stine Helene Falsig

AU - Kragelund, Birthe B

PY - 2011/5/3

Y1 - 2011/5/3

N2 - Intrinsic disorder is important for protein regulation, yet its role in regulation of ion transport proteins is essentially uninvestigated. The ubiquitous plasma membrane carrier protein Na(+)/H(+) Exchanger isoform 1 (NHE1) plays pivotal roles in cellular pH and volume homeostasis, and its dysfunction is implicated in several clinically important diseases. This study shows, for the first time for any carrier protein, that the distal part of the C-terminal intracellular tail (the cdt, residues V686-Q815) from human (h) NHE1 is intrinsically disordered. Further, we experimentally demonstrated the presence of a similar region of intrinsic disorder (ID) in NHE1 from the teleost fish Pleuronectes americanus (paNHE1), and bioinformatic analysis suggested ID to be conserved in the NHE1 family. The sequential variation in structure propensity as determined by NMR, but not the amplitude, was largely conserved between the h- and paNHE1cdt. This suggests that both proteins contain molecular recognition features (MoRFs), i.e., local, transiently formed structures within an ID region. The functional relevance of the most conserved MoRF was investigated by introducing a point mutation that significantly disrupted the putative binding feature. When this mutant NHE1 was expressed in full length NHE1 in AP1 cells, it exhibited impaired trafficking to the plasma membrane. This study demonstrated that the distal regulatory domain of NHE1 is intrinsically disordered yet contains conserved regions of transient structure. We suggest that normal NHE1 function depends on a protein recognition element within the ID region that may be linked to NHE1 trafficking via an acidic ER export motif.

AB - Intrinsic disorder is important for protein regulation, yet its role in regulation of ion transport proteins is essentially uninvestigated. The ubiquitous plasma membrane carrier protein Na(+)/H(+) Exchanger isoform 1 (NHE1) plays pivotal roles in cellular pH and volume homeostasis, and its dysfunction is implicated in several clinically important diseases. This study shows, for the first time for any carrier protein, that the distal part of the C-terminal intracellular tail (the cdt, residues V686-Q815) from human (h) NHE1 is intrinsically disordered. Further, we experimentally demonstrated the presence of a similar region of intrinsic disorder (ID) in NHE1 from the teleost fish Pleuronectes americanus (paNHE1), and bioinformatic analysis suggested ID to be conserved in the NHE1 family. The sequential variation in structure propensity as determined by NMR, but not the amplitude, was largely conserved between the h- and paNHE1cdt. This suggests that both proteins contain molecular recognition features (MoRFs), i.e., local, transiently formed structures within an ID region. The functional relevance of the most conserved MoRF was investigated by introducing a point mutation that significantly disrupted the putative binding feature. When this mutant NHE1 was expressed in full length NHE1 in AP1 cells, it exhibited impaired trafficking to the plasma membrane. This study demonstrated that the distal regulatory domain of NHE1 is intrinsically disordered yet contains conserved regions of transient structure. We suggest that normal NHE1 function depends on a protein recognition element within the ID region that may be linked to NHE1 trafficking via an acidic ER export motif.

U2 - 10.1021/bi1019989

DO - 10.1021/bi1019989

M3 - Journal article

C2 - 21425832

SN - 0006-2960

VL - 50

SP - 3469

EP - 3480

JO - Biochemistry

JF - Biochemistry

IS - 17

ER -