Differential Expression of Potassium Channels in Placentas from Normal and Pathological Pregnancies: Targeting of the Kir 2.1 Channel to Lipid Rafts
Author
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Riquelme Pino, Gloria
es_CL
Author
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De Gregorio, Nicole
es_CL
Author
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Vallejos, Catalina
es_CL
Author
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Berrios, Macarena
Author
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Morales, Bárbara
es_CL
Admission date
dc.date.accessioned
2014-01-10T14:17:05Z
Available date
dc.date.available
2014-01-10T14:17:05Z
Publication date
dc.date.issued
2012-03
Cita de ítem
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J Membrane Biol (2012) 245:141–150
en_US
Identifier
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DOI 10.1007/s00232-012-9422-x
Identifier
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https://repositorio.uchile.cl/handle/2250/129129
General note
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Artículo de publicación ISI
en_US
Abstract
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Potassium channels play important physiological roles in human syncytiotrophoblasts (hSTBs) from placenta, an epithelium responsible for maternal-fetal exchange. Basal and apical plasma membranes differ in their lipid and protein composition, and the latter contains cholesterol-enriched microdomains. In placental tissue, the specific localization of potassium channels is unknown. Previously, we described two isolated subdomains from the apical membrane (MVM and LMVM) and their respective microdomains (lipid rafts). Here, we report on the distribution of K(ir)2.1, K(v)2.1, TASK-1, and TREK-1 in hSTB membranes and the lipid rafts that segregate them. Immunoblotting experiments showed that these channels are present mainly in the apical membrane from healthy hSTBs. Apical expression versus basal membrane was 84 and 16% for K(ir)2.1 and K(v)2.1, 60 and 30% for TREK-1, and 74 and 26% for TASK-1. Interestingly, K(v)2.1 showed differences between apical membrane subdomains: 26 +/- 8% was located in the LMVM and 59 +/- 9% in MVM. In pathological placentas, the expression distribution changed in the basal membrane: preeclampsia shifted to 50% and intrauterine growth restriction to 42% for TASK-1 and both pathologies increased to 25% for K(ir)2.1 and K(v)2.1, K(ir)2.1 appeared to be associated with rafts that were sensitive to cholesterol depletion in healthy, but not in pathological, placentas. K(v)2.1 and TREK-1 emerged in the nonraft fractions. The precise membrane localization of ion channels in hSTB membranes is necessary to understand the physiological events.