G protein subunit, alpha i-3, activates a pertussis toxin-sensitive Na+ channel from the epithelial cell line, A6.

摘要: In nonpolar excitable cells, guanine nucleotide regulatory (G) proteins have been shown to modulate ion channel activity in response hormone receptor activation. polarized epithelia, receptor-G protein coupling involved the generation of cAMP occurs on basolateral membrane, while physiological this messenger is a stimulation at apical membrane. present study we utilized patch-clamp technique assess if renal A6, topologically distinct G their membrane capable modulating Na+ activity. excised inside-out patches membranes, spontaneous (conductance 8-9 picosiemens) was inhibited by addition 0.1 mM guanosine 5'-O-(2-thio)diphosphate cytosolic surface without an effect single conductance. contrast, percent open time channels increased from 6 50% following GTP. The preactivated pertussis toxin (100 ng/ml) bathing solution patch within minute 85% approximately 47 7% and reduced for zero after 3 min. 5'-(3-O-thio)triphosphate or 20 pM purified human alpha i-3 subunit toxin-treated restored 35% time. As little as 0.2 restoring These data provide evidence role toxin-sensitive plasma epithelia distal signal transduction pathways these cells. This raises possibility transducing pathway co-localized with channel.