Reciprocal regulation of Ca²+-activated outward K+ channels of Pyrus pyrifolia pollen by heme and carbon monoxide.
New Phytol
; 189(4): 1060-1068, 2011 Mar.
Article
em En
| MEDLINE
| ID: mdl-21133925
ABSTRACT
⢠The regulation of plant potassium (K+) channels has been extensively studied in various systems. However, the mechanism of their regulation in the pollen tube is unclear. ⢠In this study, the effects of heme and carbon monoxide (CO) on the outward K+ (K+(out)) channel in pear (Pyrus pyrifolia) pollen tube protoplasts were characterized using a patch-clamp technique. ⢠Heme (1 µM) decreased the probability of K+(out) channel opening without affecting the unitary conductance, but this inhibition disappeared when heme was co-applied with 10 µM intracellular free Ca²+. Conversely, exposure to heme in the presence of NADPH increased channel activity. However, with tin protoporphyrin IX treatment, which inhibits hemeoxygenase activity, the inhibition of the K+(out) channel by heme occurred even in the presence of NADPH. CO, a product of heme catabolism by hemeoxygenase, activates the K+(out) channel in pollen tube protoplasts in a dose-dependent manner. The current induced by CO was inhibited by the K+ channel inhibitor tetraethylammonium. ⢠These data indicate a role of heme and CO in reciprocal regulation of the K+(out) channel in pear pollen tubes.
Texto completo:
1
Base de dados:
MEDLINE
Medicinas Complementares:
Homeopatia
Assunto principal:
Pólen
/
Monóxido de Carbono
/
Ativação do Canal Iônico
/
Canais de Potássio Cálcio-Ativados
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Pyrus
/
Heme
Idioma:
En
Revista:
New Phytol
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
China