Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Functional integrity of the vesicle transporting machinery is required forcomplete activation of CFTR expressed in Xenopus laevis oocytes
Autore:
Weber, WM; Segal, A; Simaels, J; Vankeerberghen, A; Cassiman, JJ; Van Driessche, W;
Indirizzi:
Katholieke Univ Leuven, Physiol Lab, B-3000 Louvain, Belgium Katholieke Univ Leuven Louvain Belgium B-3000 b, B-3000 Louvain, Belgium Katholieke Univ Leuven, Ctr Human Genet, B-3000 Louvain, Belgium Katholieke Univ Leuven Louvain Belgium B-3000 t, B-3000 Louvain, Belgium
Titolo Testata:
PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY
fascicolo: 6, volume: 441, anno: 2001,
pagine: 850 - 859
SICI:
0031-6768(200103)441:6<850:FIOTVT>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
TRANSMEMBRANE CONDUCTANCE REGULATOR; EPITHELIAL SODIUM-CHANNEL; PROTEIN-KINASE-C; CYSTIC-FIBROSIS; MEMBRANE TRAFFICKING; PLASMA-MEMBRANE; NA+ TRANSPORT; ION CHANNELS; BREFELDIN-A; CAPACITANCE;
Keywords:
cystic fibrosis; exocytosis; protein trafficking; membrane capacitance; vesicular transport;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
54
Recensione:
Indirizzi per estratti:
Indirizzo: Weber, WM Katholieke Univ Leuven, Physiol Lab, Campus Gasthuisberg, B-3000Louvain, Belgium Katholieke Univ Leuven Campus Gasthuisberg Louvain Belgium B-3000
Citazione:
W.M. Weber et al., "Functional integrity of the vesicle transporting machinery is required forcomplete activation of CFTR expressed in Xenopus laevis oocytes", PFLUG ARCH, 441(6), 2001, pp. 850-859

Abstract

We expressed the human cystic fibrosis transmembrane conductance regulator(CFTR) in oocytes of the South African clawed frog Xenopus laevis. We per formed simultaneous and continuous recording of membrane current (I-m), conductance (G(m)) and capacitance (C-m), the latter being a direct measure ofmembrane surface area. A cAMP-cocktail containing cAMP and isobutylmethylxanthine (IBMX) increased all parameters, demonstrating that CFTR activationwas partly achieved by exocytotic delivery and insertion of preformed CFTRmolecules into the plasma membrane. CFTR currents after cAMP-cocktail werecorrelated with the capacitance of the oocytes: oocytes with larger C-m exhibited larger currents. Expression of CFTR itself did not change the C-m of the oocytes. However, activation of CFTR with cAMP-cocktail increased I-mand G(m) 15- and 20-fold, respectively while membrane surface area increased by about 7%, indicating the functional insertion of preformed CFTR into the plasma membrane. While cAMP-cocktail yielded maximal CFTR stimulation, IBMX alone, but not caffeine or theophylline, was sufficient to stimulate more than half of the increases in I-m and G(m) as observed with cAMP-cocktail. Since C-m was not significantly stimulated by IBMX, we conclude that IBMX alone activated the CFTR channels already present in the oocyte membrane. CFTR stimulation by cAMP-cocktail was independent of external Ca2+ and ATP had no additional activating potency. The role of protein trafficking in the activation of CFTR evoked by increases of cytoplasmic cAMP was assessedby measuring the effects of brefeldin A (BFA), nocodazole and primaquine on the bioelectric parameters and membrane surface area. All these compoundsthat interfere with the protein trafficking machinery at different stages prevented the translocation of CFTR from intracellular pools to the plasma membrane. These data confirm and extend our previous observations that CFTRexpressed in Xenopus laevis oocytes is activated via dual pathways including direct activation of CFTR already present in the membrane and exocytoticinsertion of preformed CFTR channels into the membrane. Furthermore, we show that complete activation of CFTR requires an intact protein trafficking machinery.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/01/21 alle ore 03:28:52