FIGURE 3.

Sec22(D153C) and Sec22HA(D153C) form mixed homodimers when both derivatives are expressed in the same strain. Washed semi-intact cells expressing the indicated cysteine derivatives of Sec22 and Sec22HA in CBY773 were incubated in the absence (−) or presence (+) of 0.2 mm Cu²⁺/phen. After quenching reactions with NEM, proteins were resolved on non-reducing 10% SDS-PAGE and immunoblotted with anti-Sec22 or anti-HA. Positions for the Sec22-Sec22 homodimer (22 × 22), Sec22-Sec22HA mixed dimer (22 × 22HA), and Sec22HA-Sec22HA homodimer (22HA × 22HA) are indicated by arrows. Arrows also show the positions of monomeric Sec22 and Sec22HA. The asterisks indicate unidentified cross-linked products.