Peptide sequence: AAAAANQCRN LMAHPAPLAP GAASAYSSAP GEAPPSAAAA AAAAAAAAAA Sequence homology: Dog: 83%; Human: 100%; Mouse: 92%. HoxA13 and HoxD13 also bind to other BMP and TGF-beta/Activin-regulated Smad proteins including Smad1 and Smad2, but not Smad4.