Gap junctions and connexin-interacting proteins.

Gap junctions form channels between adjacent cells. The core proteins of these channels are the connexins. Regulation of gap junction communication (GJC) can be modulated by connexin-associating proteins, such as regulatory protein phosphatases and protein kinases, of which c-Src is the best-studied. Structural proteins, notably zona occludens-1 (ZO-1) and microtubules, have been found recently at gap junctions. Along with the expansion of the list of connexin-associating proteins, reports have appeared that suggest that connexins might have additional roles in addition to their channel function, such as transcriptional and cytoskeletal regulation. Here, gap junction interacting proteins are reviewed and their function is addressed. The striking similarity of proteins present at the cytoplasmic face of tight junctions, adherens junctions and gap junctions and their possible role in gene transcription and cytoskeletal anchorage is highlighted.