|
ИСТИНА |
Войти в систему Регистрация |
ИСТИНА ИНХС РАН |
||
Actin-based regulation of ENaC-like sodium channels in leukemia cell linesстатья Тезисы
- Авторы: Sudarikova A., Vassilieva I., Negulyaev Y., Morachevskaya E., Chubinskiy-Nadezhdin V.
- Журнал: Proceedings of The Physiological Society
- Том: 37
- Год издания: 2016
- Первая страница: PCA126
- Последняя страница: PCA126
- Аннотация: Actin cytoskeleton is one of the important cellular systems that are structurally and functionally coupled with ion channels in plasma membrane. We have previously shown that function of non-voltage-gated sodium channels in human leukemia K562 cells is critically dependent on actin dynamics. In recent years, leukemia-lymphoma cell lines are extensively used as appropriate cellular models to study the role of ion-transporting systems in hematologic malignancies. In the present work, we used different modes of patch clamp technique to examine ion channels involved in Na-transporting pathway in U937 human lymphoma cells. The activity of native sodium-selective channels with unitary conductance of 10-11 pS was revealed in cell-attached, inside-out and whole-cell configurations. Patch-clamp data indicated principal similarity of functional properties of the channels in K562 and U937 cells. Sodium channel activity in leukemia-lymphoma cell lines was directly controlled by submembranous actin cytoskeleton. Specifically, an activation of sodium channels in U937 cells in response to microfilament disruption by cytochalasin D was demonstrated on single-channel and integral current level. Inside-out experiments with the use of globular actin showed that filament assembly on cytoplasmic membrane surface caused fast inactivation of the channels. Biophysical characteristics of non-voltage-gated sodium channels in leukemia cell lines were similar to that of epithelial sodium channels (ENaCs). Consistently, an expression of alpha-, beta-, gamma-hENaC subunits in K562 and U937 cells was detected using RT-PCR and immunofluorescent staining. However, we showed that amiloride (up to 0.1 mM), known inhibitor of DEG/ENaC, did not block single sodium channels; whole-cell current measurements revealed no amiloride-sensitive component of membrane current. Interestingly, we found that sodium channel activity was drastically increased in response to extracellular application of trypsin (5 mkg/ml). Taken together, our observations suggest that amiloride-insensitive sodium channels in K562 and U937 cells belong to the ENaC family. We conclude that cortical actin structures represent the main factor that controls the activity of ENaC-like channels in human leukemic cells.
- Добавил в систему: Негуляев Юрий Алексеевич