Figure 9.

Gea1p and Gea2p cofractionate with cis-Golgi proteins. Strain YAS61 (Gea2p-myc-his₆) was grown to early log phase. A membrane pellet of a 10,000 × g spin was floated to equilibrium on a sucrose gradient. Fractions were collected from the top. The fractions were either separated by SDS-PAGE, and analyzed by immunoblot with antibodies directed against Gea1p, the myc-epitope (Gea2p-myc-his₆), Anp1p, Emp47p, Sed5p, Bos1p, and Arf1p (A) or sampled for GDPase activity assays (B). The arrow in A indicates the direction of movement of membranes within the gradient.