Fig. 4. The presence of a shared domain in components of the COG complex and the exocyst. (A) Sequence alignment of the N-terminal amphipathic helical regions of the indicated components of the human COG complex and exocyst. Residues are shaded if identical (black) or conserved (grey) in at least three proteins. Grey bars show the regions predicted to form coiled-coil (the hydrophobic heptad repeat indicated by black circles). (B) Prediction of the propensity of the subunits of the human COG complex and human exocyst to form coiled coils. The length of the x-axis corresponds to the length of the proteins, with residue numbers indicated at the bottom of the figure. On the y-axis is plotted the probability of a coiled-coil being at each residue of the protein, as determined by the algorithm of Lupas (Lupas, 1996) using the MacStripe program (v2.0b1) with a window length of 28 residues, the MTIDK matrix and weighting of hydrophobic residues. Red bars indicate regions that are aligned in (A). Blue bars indicate longer regions of sequence similarity between Cog3, Cog6 and Exo70 [see alignment in Whyte and Munro (Whyte and Munro, 2001)].