Patch-clamp study of liver nuclear ionic channels reconstituted into giantproteoliposomes

Nuclear ionic channels (NICs) represent ubiquitous structures of living cel ls, although little is known about their functional properties and encoding genes, To characterize NICs, liver nuclear membrane vesicles were reconsti tuted into either planar lipid bilayers or proteoliposomes. Reconstitution of nuclear envelope (NE) vesicles into planar lipid bilayer proceeded with low efficiency. NE vesicle reconstitution into proteoliposomes led to NIC o bservations by the patch-clamp technique. Large conductance. voltage-gated, K+-permeant and Cl--permeant NICs were characterized. An 80-105-pS K+-perm eant NIC with conducting sub-state was also recorded. Our data establish th at NICs can be characterized upon reconstitution into giant proteoliposomes and retain biophysical properties consistent with those described for nati ve NICs, (C) 2000 Federation of European Biochemical Societies, Published b y Elsevier Science B.V. All rights reserved.