RESUMO
Voltage-activated Ca2+ channels are membrane protein machinery performing selective permeation of external calcium ions. The main Ca2+ selective filters of all high-voltage-activated Ca2+ channel isoforms are commonly composed of four Glu residues (EEEE), while those of low-voltage-activated T-type Ca2+ channel isoforms are made up of two Glu and two Asp residues (EEDD). We here investigate how the Asp residues at the pore loops of domains III and IV affect biophysical properties of the Ca(v)3.2 channel. Electrophysiological characterization of the pore mutant channels in which the pore Asp residue(s) were replaced with Glu, showed that both Asp residues critically control the biophysical properties of Ca(v)3.2, including relative permeability between Ba2+ and Ca2+, anomalous mole fraction effect (AMFE), voltage dependency of channel activation, Cd2+ blocking sensitivity, and pH effects, in distinctive ways.
Assuntos
Ácido Aspártico/química , Canais de Cálcio Tipo T/metabolismo , Sequência de Aminoácidos , Animais , Bário/metabolismo , Cádmio/metabolismo , Cálcio/metabolismo , Canais de Cálcio Tipo T/química , Canais de Cálcio Tipo T/genética , Feminino , Humanos , Concentração de Íons de Hidrogênio , Mutagênese , Oligopeptídeos/química , Oócitos/fisiologia , Técnicas de Patch-Clamp , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Xenopus/crescimento & desenvolvimento , Xenopus/fisiologiaRESUMO
A case of arthrogryposis multiplex congenita is an extremely rare and complex syndrome characterized by contractures of multiple joints in different parts of the body. Arthrogryposis multiplex congenita usually occurs alone but may be associated with other malformations. We experienced a case of arthrogryposis multiplex congenita, so report the case with relat ed literatures.
