Second mutations rescue point mutant of the Na+/H+ exchanger NHE1 showing defective surface expression

FEBS Letters

Pang, Tianxiang¹  Su, Xiaohua¹  Wakabayashi, Shigeo¹  Shigekawa, Munekazu¹ 

[1] Department of Molecular Physiology, National Cardiovascular Center Research Institute, Fujishiro-dai 5, Suita, Osaka 565, Japan

关键词: Na+/H+ exchanger;    Plasma membrane targeting;    Membrane topology;    Transmembrane domain;    Site-directed mutagenesis;    Revertant;    NHE;    Na+/H+ exchanger;    DiOC6(3);    3;    3′-dihexyloxacarbocyanine iodide;    EIPA;    5-(N-ethyl-N-isopropyl) amiloride;    PBS;    phosphate-buffered saline;    aa;    amino acid(s);    TM;    transmembrane segment;   

DOI  :  10.1016/S0014-5793(00)02348-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We studied the effect of point mutation within the putative 11th transmembrane domain (TM11) of the Na⁺/H⁺ exchanger NHE1 on the plasma membrane expression. Of the 19 mutants tested, two mutants (Tyr454 or Arg458 replaced by Cys) were retained in the endoplasmic reticulum. Interestingly, Y454C was expressed on the cell surface when one of the endogenous cysteine residues at position 8, 133, 421, or 477 was substituted with alanine. Random mutagenesis at Cys8 and its surrounding residues in the cytosolic N-tail revealed that replacement of Cys8 with Ala was the only identified single residue mutation that rescued Y454C. These results suggest that the abnormal conformation of the region of TM11 containing the Y454C mutation is compensated by the second mutation within other domains such as the N-tail. This approach may provide evidence for the interdomain interaction in NHE1.

【 授权许可】

Unknown