Required for targeting of connexins to the plasma membrane. Interacts with connexins GJA1/CX43, GJB1/CX32, GJB2/CX26, GJB3/CX31, GJB6/CX30 and GJC1/CX45. Also interacts with GGA1 and GGA2. Does not interact with PANX1 (By similarity). Located predominantly in the trans-Golgi network. Probably trafficks between the trans-Golgi network and the cell membrane via the secretory pathway. Belongs to the CNST family. Extended N-terminus.