Double-membrane gap junction internalization requires the clathrin-mediated endocytic machinery

Abstract 

Direct cell–cell communication mediated by plasma membrane-spanning gap junction (GJ) channels is vital to all aspects of cellular life. Obviously, GJ intercellular communication (GJIC) requires precise regulation, and it is known that controlled biosynthesis and degradation, and channel opening and closing (gating) are exploited. We discovered that cells internalize GJs in response to various stimuli. Here, we report that GJ internalization is a clathrin-mediated endocytic process that utilizes the vesicle-coat protein clathrin, the adaptor proteins adaptor protein complex 2 and disabled 2, and the GTPase dynamin. To our knowledge, we are first to report that the endocytic clathrin machinery can internalize double-membrane vesicles into cells.

Abbreviations: AGJ, annular gap junction, AP-2, adaptor protein complex 2, CHC, clathrin heavy chain, CME, clathrin-mediated endocytosis, Cx, connexin, Dab2, disabled 2, GJ, gap junction, KD, knockdown, PM, plasma membrane, RNAi, RNA interference, Trfn, transferrin

Keywords: Annular gap junction, Clathrin, Connexin, Endocytosis, Gap junction, RNAi