Figure 3.

Working model of how TARA promotes sleep. TARA upregulates CycA, which negatively regulates Cdk1 activity in the PL neurons. We propose that increased activity of Cdk1 leads to an increase in the excitability of PL neurons, which promotes wakefulness and feeding. We further speculate that TARA levels and/or activity are modulated by sleep debt and satiety. The two diagrams depict PL neurons when flies have high sleep debt and satiety (left) and when they have low sleep debt and satiety (right), respectively. The mammalian counterparts are indicated in parentheses, and broken lines represent connections that need further investigation.