Connexin and gap junction degradation

Many of the subunit proteins (connexins) that form gap junctions are rather dynamic, with half-lives of only a few hours. Thus, alterations in connexi n turnover and degradation may represent significant mechanisms for the reg ulation of intercellular communication. We describe a pharmacological appro ach to determining pathways of connexin degradation. Cell cultures are left untreated or treated with inhibitors of lysosomal or proteasomal proteolys is. Changes in connexin levels, localization, or decay curves (derived from pulse-chase experiments) are assessed by immunoblotting, immunofluorescenc e, and immunoprecipitation, respectively. Such experiments have provided ev idence that connexin43 degradation involves both the lysosome and the prote asome, (C) 2000 Academic Press.