Intercellular communication in lens development and disease

Gap junctions provide an important pathway for the intercellular transport of molecules needed for lens growth and homeostasis (Goodenough 1992; White and Bruzzone 2000). In the lens, three different connexin subunits, connexin43 (Cx43), connexin46 (Cx46), and connexin50 (Cx50), contribute to the intercellular channels that comprise gap junctions (Gerido andWhite 2004). Each of these connexins has unique gating and permeation properties (Srinivas et al. 1999; Hopperstad et al. 2000; Valiunas et al. 2002), suggesting that the lens requires functionally distinct types of intercellular communication. Gap junction channels are particularly important in the lens, as they provide a major route for the exchange of essential molecules between the metabolically active epithelium and the quiescent fiber cell core (Mathias et al. 1997; Donaldson et al. 2001).