Fig. 2. ECM modulates connexin protein expression and localization of CID-9 cells cultured in differentiation medium on day 6 of culture. (A) Western blot analysis of Cx26, Cx32 and Cx43. Cells were plated on plastic (Pl), EHS-drip (Ed) or EHS-matrix (Ec). P2, P1 and NP denotes the different phosphorylation states of Cx43. Cx43 P2 form was signifcanlty (P<0.001) upregulated in cells on Ec compared with those on Pl or Ed. (B) Immunolocalization of connexins in CID-9 cells, plated on plastic (a,c,e) and on EHS-drip (b,d,f). Cells were immunostained for Cx26 (a,b), Cx32 (c,d) and Cx43 (e,f). Note predominant membranous localization of connexins in cells cultured on EHS-drip (b,d,f). Inserts in (a), (c) and (e) show occasional membranous localization noted in cells cultured on plastic.