Nucleotide-activated chloride channels in lysosomal membranes.
Lysosomal membrane vesicles purified from rat liver contain a basal chloride conductance that was enhanced in the presence of ATP, non-hydrolysable ATP-analogs and, to a lesser extent, GTP. Other nucleotides, including AMP, ADP and cAMP, as well as CTP and UTP were not effective. Following fusion of the vesicles with an artificial phosphatidylethanolamine/phosphatidylserine bilayer, we found that ATP gamma S dramatically increased the incidence of 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS)-sensitive chloride channels with a unitary slope conductance of approx. 40 pS in 300 mM/50 mM KCl buffers and 120 pS in symmetrical 300 mM KCl buffers. Since similar results were obtained with AMP-PNP, the results indicate that lysosomes contain a chloride permeable ion channel that is activated by ATP through allosteric interaction.
Tilly
B C
BC
Department of Biochemistry, Erasmus University, Rotterdam, The Netherlands.
Mancini
G M
GM
Bijman
J
J
van Gageldonk
P G
PG
Beerens
C E
CE
Bridges
R J
RJ
de Jonge
H R
HR
Verheijen
F W
FW
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002021:Buffers; D018118:Chloride Channels; D004553:Electric Conductivity; D006160:Guanosine Triphosphate / Q000494:pharmacology; D007425:Intracellular Membranes / Q000378:metabolism*; D008051:Lipid Bilayers / Q000378:metabolism; D008099:Liver / Q000648:ultrastructure*; D008247:Lysosomes / Q000648:ultrastructure*; D008565:Membrane Proteins / Q000378:metabolism*; D009711:Nucleotides / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats
D002021:Buffers; D018118:Chloride Channels; D008051:Lipid Bilayers; D008565:Membrane Proteins; D009711:Nucleotides; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; C022571:adenosine 5'-O-(3-thiotriphosphate); D011189:Potassium Chloride; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid