Figure 9.

The rapid aging of sip2Δ cells is accompanied by increases in hexokinase activity and energy storage. (A) Hexokinase activity was measured in lysates prepared from individual mothers recovered at the indicated generations. Mean values ± 1 s.d. are plotted. (Asterisk) Values are significantly different (P < 0.05; Student's t-test) from generation 0–1 wild-type cells. (B) 2DG6P accumulation as a function of time in isogenic wild-type and sip2Δ cells. (C,D) Cellular ATP and NAD⁺ levels. The number of independently generated lysates/cell population/generational time point is noted (n = 50,000 cells assayed/lysate/experiment). Note that generation 4 in sip2Δ cells and generation 6–8 in wild-type cells represent equivalent fractions of their total lifespans. (E) Summary of fold differences in hexokinase, G6P, ATP, and NAD⁺ levels relative to young wild-type cells.