Ubiquitination, intracellular trafficking, and degradation of connexins

Gap junction channels provide a conduit for communication between neighboring cells. The function of gap junction channels is regulated by posttranslational modifications of connexins, the proteins that comprise these channels. Ubiquitination of connexins has increasingly been viewed as one mechanism by which cells regulate the level of connexins present in cells, as well as the corresponding intercellular communication. Here we review the current knowledge of connexin ubiquitination and the effects this may have on gap junctional communication.

► Connexin43 ubiquitin modification affects intracellular trafficking and degradation.
► Monoubiquitination affects connexin43 internalization and endosomal trafficking.
► Ubiquitination is involved in connexin32 proteasomal degradation.
► Ubiquitination is not required for CIP75-mediated connexin43 proteasomal degradation.