Introduction 2002 2002 2003 2006 2002 2002 1 1982 2002 Fig. 1 General structure of a gap junction plaque. Gap junctions are formed by paired hemichannels (connexons) of two adjacent cells. A single connexon is made by a polymer of six connexins. Only apposed connexons allow intercellular transfer of ions (ionic coupling) and small metabolites (metabolic coupling). Unapposed connexons seem to perform per se functions  In the following, we will put main emphasis on heart and brain tissues for which most of the data on gap junctions and cell adhesion have been reviewed. Cardiomyocytes: directed trafficking of connexin43 involves the cytoskeleton and adhesion plaques 1996 1997 2001 2 2003 2003 2006 2003 Fig. 2 a red b red  2006 2007 2000 2003 2007 1996 1997 1998 1998 1991 1999 2004 trans 1993 2005 1999 2002 2005 2007 2002 2005 2004 1999 1997 2005 2003 1999 1999 2003 2005 2007 2007 1999 2000 2001 2007 2007 3 2003 Fig. 3 2007 +  2001 2003 Shigella flexneri Shigella flexneri 2008 1964 2003 2000 2000 S flexneri 1994 2008 2000 2004 1997 1995 2001 2004 The developing brain and hemichannel adhesion 2001 2006 2000 2001 1971 1972 1988 1998a 1989 2007 2007 Neural crest cells and colonization 2007 2005 1998a b 2002 1999 1995 1995 2001 2006 1995 2006 1983 1991 2006 1994 1997 2003 2004 2008 2006 2001 2001 2001 2005 2003 2003 2006 2004 2005 1998 2005 In summary, asides their function as gap junction forming elements, unpaired connexons have been shown to modulate the cells’ migratory and adhesive functions whilst being in permanent crosstalk with an elaborate complex of cytoskeletal interaction partners. Perspectives on pathology 2003 2007 2003 2002 2001 2006 2002 2000 2002 2006 2002 2003 At its final extent, gap junction channels, in particular in form of hemichannels, constitute a new player in the complex interaction of cell adhesion and cytoskeletal activation, which underlies directed migration during development and in mature tissue. It is a romantic phase where anything may go, but time has to approve what will remain forever.