Figure 9.

Overexpression of SEC63 partially suppresses the cold sensitivity of a subset of sec61 mutant strains by enhancing translocation. (A) Strains with the indicated plasmids were streaked onto SC plates minus uracil and incubated at 30°C for 3 d or 17°C for 5 d. pDF15 is a 2μ vector with the full-length SEC63 sequence. pRS426 is a multicopy vector used as a control. (B) Indicated strains carrying either pRS426 control plasmid (−) or the 2μ-SEC63 plasmid pDF15 (+) were pulse labeled at 17°C followed by immunoprecipitation as in Figure 2. The positions of precursor forms (pDPAPB, pKar2p, preproCPY, and ppαf), signal-cleaved, unglycosylated proteins (Kar2p and pαf), and signal-cleaved, glycosylated forms (DPAPB, p1, and 3 gpαf) are indicated. The band marked with an asterisk is unrelated.