LLC-PK sub 1 mutant with increased Na sup + -H sup + exchange and decreased sensitivity to amiloride

Journal Article · Sat Oct 01 04:00:00 EDT 1988 · American Journal of Physiology; (USA)

OSTI ID:6037332

Haggerty, J G; Agarwal, N; Cragoe, Jr, E J; Adelberg, E A; Slayman, C W ^[1]

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1. Yale Univ. School of Medicine, New Haven, CT (USA) Merck Sharp Dohme Research Laboratories, West Point, PA (USA)

LLC-PK{sub 1} cells contain a well-characterized Na{sup +}-H{sup +} antiporter that is sensitive to ethylisopropylamiloride (EIPA) in the submicromolar range. Using a modification of the method of Franchi et al., the authors have selected mutants that can recover from an acid load in the presence of EIPA. One such mutant, designated PKE20, has been studied in detail. The maximal velocity (V{sub max}) for the Na{sup +}-H{sup +} antiporter, assayed as EIPA-sensitive {sup 22}Na{sup +} uptake, has increased from 44 to 106 nmol{center dot}min{sup {minus}1}{center dot}10{sup 6} cells{sup {minus}1} in PKE20. No detactable change has occurred in the K{sub m} for Na{sup +} or in the dependence of Na{sup +} uptake on intracellular pH. However, the PKE20 antiporter exhibits a greatly decreased sensitivity to amiloride and its derivatives, with drops in inhibitory potency ranging from 25-fold (amiloride) to 100-fold (EIPA). The mutation is specific for the antiporter; measurements of Na{sup +}-K{sup +} pump and Na{sup +}-dependent amino acid uptake show only small changes, which appear to result from minor antiporter-induced alterations in internal Na{sup +} concentration. PKE20 cells should prove useful in experiments to identify and isolate the antiporter protein.

• OSTI ID: 6037332
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 255:4; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ANIMAL CELLS
BARYONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
DAYS LIVING RADIOISOTOPES
DIURETICS
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LIGHT NUCLEI
MEMBRANE PROTEINS
MEMBRANE TRANSPORT
MINUTES LIVING RADIOISOTOPES
MUTANTS
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PH VALUE
PROTEINS
PROTONS
RADIOISOTOPES
RUBIDIUM 86
RUBIDIUM ISOTOPES
SENSITIVITY
SODIUM 22
SODIUM COMPOUNDS
SODIUM ISOTOPES
YEARS LIVING RADIOISOTOPES