Molecular Biology of Mammalian Gap Junctions
Numerous recent reviews and monographs can guide the reader through almost all aspects of gap junction biology. This field entered the age of molecular genetics when the first cDNA codings for gap junction proteins were published 3 years ago. Since there is no apparent enzymatic activity associated with these cellular structures, gap junctions had to be purified from rat and mouse liver under conditions in which the preserved plaque structure could be used as a criterion for purification. Using rabbit antibodies to the 27-kDa rat liver protein, the complete cDNA corresponding to this protein was isolated from a lambda gtll cDNA expression library. The variability of the intracellular domains of the different connexin molecules suggests that these proteins may interact with different secondary molecules, which may recognize different motifs on different connexin molecules. The exploration of gap junction structure has been aided enormously by application of the methods of molecular biology.