Table 2.

Quantification of the Decrease in Relative ER Surface Area in the Mutants with Disrupted ER Structure

Strain	Relevant genotype	25°C	37°C
FY23	Wild-type	1.36 ± 0.12	1.32 ± 0.16
WPY154	srp101-47	1.03 ± 0.18	0.66 ± 0.08
WPY152	srp102-510	1.07 ± 0.09	0.26 ± 0.04
WPY153	sec27-95	1.01 ± 0.10	0.80 ± 0.09

The relative ER surface area, μm² ER (both perinuclear and cortical) per μm³ cell volume, was determined by EM on ultrathin sections of KMnO₄-fixed cells grown at 25°C, or after a 3-h shift to 37°C. Values are the average of 100 cells ± SD.