The intracellular lipid-binding domain of human Na+/H+ exchanger 1 forms a lipid-protein co-structure essential for activity

Hendus-Altenburger, Ruth; Vogensen, Jens; Pedersen, Emilie Skotte; Luchini, Alessandra; Araya-Secchi, Raul; Bendsoe, Anne H.; Prasad, Nanditha Shyam; Prestel, Andreas; Cardenas, Marite; Pedraz-Cuesta, Elena; Arleth, Lise; Pedersen, Stine F.; Kragelund, Birthe B.


Dynamic interactions of proteins with lipid membranes are essential regulatory events in biology, but remain rudimentarily understood and particularly overlooked in membrane proteins. The ubiquitously expressed membrane protein Na+/H+-exchanger 1 (NHE1) regulates intracellular pH (pH(i)) with dysregulation linked to e.g. cancer and cardiovascular diseases. NHE1 has a long, regulatory cytosolic domain carrying a membrane-proximal region described as a lipid-interacting domain (LID), yet, the LID structure and underlying molecular mechanisms are unknown. Here we decompose these, combining structural and biophysical methods, molecular dynamics simulations, cellular biotinylation- and immunofluorescence analysis and exchanger activity assays. We find that the NHE1-LID is intrinsically disordered and, in presence of membrane mimetics, forms a helical alpha alpha -hairpin co-structure with the membrane, anchoring the regulatory domain vis-a-vis the transport domain. This co-structure is fundamental for NHE1 activity, as its disintegration reduced steady-state pH(i) and the rate of pH(i) recovery after acid loading. We propose that regulatory lipid-protein co-structures may play equally important roles in other membrane proteins. Hendus-Altenburger et al. provide biochemical, structural and functional information on the lipid interaction domain (LID) of the Na+/H+ Exchanger 1 (NHE1). They find that NHE1-LID is intrinsically disordered, but, when allowed to interact with a lipid membrane, forms a helical alpha alpha -hairpin, stabilized by hydrophobic and electrostatic interactions. This co-structure is fundamental for NHE1 activity, giving insight into membrane protein regulation via disordered domains.

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Título según WOS: ID WOS:000598831000003 Not found in local WOS DB
Volumen: 3
Número: 1
Editorial: Nature Research
Fecha de publicación: 2020


Notas: ISI