Figure 1. Sequence homology and domains of the NH₂-terminal tails of NKCC1 & NKCC2.

A. Schematic comparison of NKCC1 and NKCC2 amino terminal tails from vertebrates: mammal (Homo sapiens), bird (Gallus gallus), reptile (Anolis carolinensis), amphibian (Xenopus laevis), bone fish (Oreochromis niloticus), and cartilage fish (Squalus acanthias). Identical residues are highlighted in red, conserved residues are highlighted in green, blocks of identical residues are shown in blue, and non-conserved residues are indicated in white (gaps). Note the presence of 2-3 regions of high degree of conservation, corresponding to the SPAK/OSR1 binding motifs, and the phospho-threonines and -serines. Bars indicate the RFxV motifs or SPAK/OSR1 binding site (filled bar), and the VxFxD motif or PP1 binding site (open bar). B. Amino acid alignment of a portion of the N-terminal tail of human and mouse NCC, NKCC1, and NKCC2. Protein sequences were aligned using VectorNti (Invitrogen) and a portion of the alignment is displayed. Threonine and serine residues that are targets of phosphorylation are highlighted with references. The position of the R5 peptide used to generate the R5 antibody [38] is indicated. Residues highlighted in yellow are identical residues, whereas amino acids highlighted in green/blue represent conserved residues.