Model of the TM4-Cx43CT construct. A) Schematic diagram of full length Cx43. The black coloring represents the TM4-Cx43CT portion. The abbreviations are as follows: NT, N-terminus; CL, cytoplasmic loop; CT, C-terminus; EL1 and EL2, extracellular loops 1 and 2; 1–4, transmembrane segments 1–4. B) Amino acid sequence of the TM4-Cx43CT construct. The EL2 (line), TM4 (bold), and the CT (arrow) domains have been labeled. The asterisk denotes that the study used to determine the Cx43CT residues affected by the c-Src SH3 domain used a soluble version of the Cx43CT without the TM4 domain (28).