Figure 4.

Comparison of rat and human HCN2 phosphosites. (A) Amino acid sequences of rat and human HCN2 are juxtaposed. Green highlights show regions of each HCN sequence that were observed by mass spectrometry. Ovals indicate detected phosphosites; red labels indicate novel phosphosites; bold labels indicate phosphosites observed in ≥ 50% of either species’ samples. Structural features of HCN channels are denoted: the intracellular N-terminal region, the six transmembrane domains (S1-S6), and an extensive intracellular C-terminal region incorporating the pore-forming region and the cyclic nucleotide binding domain (CNBD). (B) Representation of the rat HCN2 channel showing phosphosites that were phosphorylated in at least 50% of rat samples (with red labeling denoting novel phosphosites). (C) Representation of the human HCN2 channel showing phosphosites that are homologous to the prevalent rat phosphosites shown in (B).