α integrin alignments (amino terminal end of the molecules). The major structural features of alpha integrins lacking an alpha-A domain are conserved in AmItgα1 including seven FG-GAP repeats (underlined, roman numerals), three DxD/NxD/NxxxD cation binding sites (double underline), the transmembrane region (long wavy line) and the cytosolic membrane proximal domain (short wavy line). The position of a putative fourth cation binding site in the Podocoryne sequence is indicated in red. Arrows mark the positions where regions that could not be unambiguously aligned were removed from the Drosophila (DmPS2; 219 residues), Caenorhabditis (CePat2; 132 residues) and human (HsItgαV; 6 residues) sequences. Abbreviations and database accession numbers for sequences used in the alignment are: Acropora AmItgα1 (AmItgα1; EU239371); Podocoryne IntA (PcIntA; AAG25993); Drosophila αPS2 (DmPS2; P12080); Mouse α9 (MmItgα9; NP_598482); Human αV (HsItgαV; P06756); Caenorhabditis αPat2 (CePat2; P34446).