FIGURE 9.

Left, UCP2 regulation as the balance of opposing transcriptional and translational regulation in non-overexpressing cells. Right, time course of changes in UCP2 protein levels and associated changes in mitochondrial OXPHOS. Transcriptional (TS) and translational (TL) regulation of UCP2 are shown relative to ERBB2-mediated and time-delayed systemic transcriptional responses as well as rapid changes in glucose uptake, described first for skeletal muscle (53). Depending on the glucose supply and subsequent up-regulation of GLUT transporter species, glucose supply may be sustained or not. The time window between the rapid relocation of previously synthesized GLUT transporters to the surface and ERBB-initiated transcriptional responses constitutes a potential “adaptation gap” during which mitochondrial activity is transiently reduced, thus favoring anaerobic utilization of glucose and minimizing spikes in ROS production.