Fig. 1. Alignment of the T. brucei ARF protein family with related sequences. Residues and motifs conserved in ARFs are highlighted in dark grey. These include the GDP/GTP - and ß-phosphate binding site GLDXAGKT, of which the threonine residue is essential for binding to guanine nucleotide exchange factors; WDXGGQ, which interacts with the purine ring of GTP; and NKXD, which binds magnesium and the ß phosphate of GTP. Several Arf-specific residues are found in the majority of the parasite proteins, including N48, W79, R100 and G165. N-myristoylation motifs are indicated by blue shading. Residues essential for binding to GRIP domain proteins are highlighted in yellow.