Multiple sequence alignment of eight Sec7 domains. Selected members of the Sec7 family were aligned by using CLUSTALW. (See Methods for the protein names and accessions.) Sequences are coloured by percentage identities: dark purple, >80%; purple, 60% ~ 80%; light purple 40% ~ 60%; white, <40%. The red box shows the conserved motif in Sec7 domain. BIG3 lacks the conserved motif, especially the critical glutamate residue (indicated by the red asterisk).