Figure 2
From: Coupling histone homeostasis to centromere integrity via the ubiquitin-proteasome system
A model for the mechanism of Ams2 protein oscillation. Ams2 binds 5' flanking regions of core histone genes, thereby activating histone gene expression. Thereafter, Ams2 is phosphorylated by DDK and its phosphorylated form is recognised by SCFPof3-ubiquitin ligase. Ubiquitylated Ams2 is then degraded by the proteasome, resulting in repression of histone gene transcription.