Models for sNKCC1, hNKCC1, two chimeras, and five point mutations in transmembrane domain 2 of sNKCC1 based on proposed structure (3). Amino acid residues are color coded according to their source: blue, hNKCC1; red, sNKCC1; yellow, rNKCC2A; green, hNCC (or TSC). Gray symbols in left model represent residues that are identical between sNKCC1 and hNKCC1.