Figure 3.

Secretion defects caused by depletion of Sec24p. (A) RSY875, carrying SEC24 expressed from the GAL1 promoter, was grown to log phase. After washing, the culture was divided into two portions and transferred to either fresh MVCA (galactose) or MVCA (glucose) at 30°C, and growth was monitored. To keep exponential growth, cultures were diluted 10-fold after 10 h. (B) A culture of RSY875 was transferred to MV-lowS (galactose) (lanes 1, 2, 5, 6, 9, and 10) or MV-lowS (glucose) (lanes 3, 4, 7, 8, 11, and 12). After 9, 12, or 15 h of cultivation at 30°C, 3.0-OD₆₀₀-unit cells were pulse labeled with [³⁵S]methionine for 10 min (lanes marked with P) and then chased for 60 min with an excess of unlabeled methionine (lanes marked with C). CPY was immunoprecipitated and analyzed by SDS-PAGE and autoradiography. p1, p2, and m represent p1 precursor (67 kDa), p2 precursor (69 kDa), and mature form (61 kDa) of CPY, respectively. Bands marked with arrowheads (60 kDa) may represent untranslocated precursors.