Bulk Isolation of Mouse Hepatocyte Gap Junctions

The gap junction is a specialized contact between adjacent cells in a wide variety of tissues (1, 2) which is thought to mediate electrotonic coupling (3) . This junction is characterized by a hexagonal lattice of subunits which may be seen in lanthanum-impregnated, negative-stained, and freezefractured preparations (1) . A method for isolation of morphologically intact gap junctions from mouse liver has been published (4), which takes advantage of the gap junction's unique insolubility in the detergent n-lauroyl sarcosine . Analysis of gap junction biochemistry and structure has been limited by the small amounts of material produced by this isolation method . This communication reports a method for bulk isolation of hepatocyte gap junctions, resulting in milligram quantities of pure junctions suitable for structural studies. In addition, new data are presented on the chemistry of the principal protein of the gap junction .