Figure 2

Evolution of type VI IF proteins. A) Amino acid sequence alignment of the helix termination motif at the end of segment 2B of the α-helical rod domain of type VI IF proteins, desmin and NF-M from different vertebrate species. Asterisks represent amino acid residues specifically conserved in tanabin, transitin and nestin. The consensus sequence deduced from this multiple alignment is indicated at the bottom of the figure. The histogram indicates the level of residue conservation (from 0 to 100%) at each position. B) A phylogenetic tree was constructed based on the protein sequences of type IV NF-M and of type VI tanabin, transitin, nestin and synemin from different species using neighbor-joining methods (CLCbio software; 100 bootstraps). A closer evolutionary relationship is noticed between tanabin, transitin and nestin. The bootstrap values are shown at the nodes. xl, Xenopus laevis; xt, Xenopus tropicalis; gg, Gallus gallus; rn, Rattus norvegicus; mm, Mus musculus; hs, Homo sapiens.