Summary
Detergent-solubilized ovine lens membrane proteins, enriched in the 70-kDa gap junction component (MP70), were reconstituted into planar lipid bilayers and analyzed for channel activities. Three distinct activities were found. Those showing conductance steps of 290 pS (symmetrical 150-mM KCl solutions) had properties similar to those reported earlier for MIP26 (Ehring, G.R., Zampighi, G., Horwitz, J., Bok, D., Hall, J.E. 1990. J. Gen. Physiol. 96:631–664.) of which minor amounts were normally present in the detergent-solubilized preparations. Two novel channel activities had unitary conductances of 90 and 45 pS, were halothane sensitive and did not discriminate between sodium and potassium ions. The 90-pS channel was asymmetrically voltage dependent, and its properties would be consistent with the expected properties of junctional hemichannels.
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This work was supported by grants from the Health Research Council of New Zealand, from the New Zealand Lottery Grants Board and from the New Zealand Vice Chancellor's Committee Fund.
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Donaldson, P., Kistler, J. Reconstitution of channels from preparations enriched in lens gap junction protein MP70. J. Membarin Biol. 129, 155–165 (1992). https://doi.org/10.1007/BF00219511
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DOI: https://doi.org/10.1007/BF00219511