Once transported to the plasma membrane, junctional channels aggregate into clusters forming gap junction plaques that may contain a few to many thousands of individual channels and that vary in size from a few square nanometers to many square micrometers (Bruzzone et al. 1996; Falk 2000; Severs et al. 2001). Gap junction plaques are involved in numerous processes including growth and differentiation (Loewenstein and Rose 1992), pathological cell proliferation (Roger et al. 2004; Segretain et al. 2003) and spermatogenesis (Juneja et al. 1999; Plum et al. 2000). The physiological importance of gap junction plaques is underscored by the diverse pathologies associated with connexin gene mutations (De Maio et al. 2002). An arbitrary number (10) of channels is shown as aggregating in this reaction but the actual number may be hundreds to thousands.