An aspartic acid residue important for voltage-dependent gating of human muscle chloride channels.
Neuron
; 15(2): 463-72, 1995 Aug.
Article
em En
| MEDLINE
| ID: mdl-7646898
ABSTRACT
A point mutation (D136G) predicting the substitution of glycine for aspartate in position 136 of the human muscle Cl- channel (hClC-1) causes recessive generalized myotonia. Heterologous expression of a recombinant D136G produces functional Cl- channels with profound alterations in voltage-dependent gating, without concomitant changes in pore properties. The mutant exhibits slowly activating current upon hyperpolarization, in contrast to wild-type channels, which display time-dependent current decay (deactivation) at negative membrane potentials. Steady-state activation of D136G depends upon the transmembrane Cl- gradient, reaching zero at voltages positive to the Cl- reversal potential in physiological Cl- distribution. This explains the reduced sarcolemmal Cl- conductance that causes myotonia. The functional disturbances exhibited by D136G may stem from a defect in the ClC-1 voltage sensor.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ativação do Canal Iônico
/
Mutação Puntual
/
Ácido Aspártico
/
Canais de Cloreto
/
Músculo Esquelético
/
Proteínas Musculares
/
Miotonia Congênita
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Neuron
Assunto da revista:
NEUROLOGIA
Ano de publicação:
1995
Tipo de documento:
Article