Zinc Finger, CCHC Domain Containing Protein 8 (ZCCHC8)

Phosphorylation of c-Myc on threonine 58 (T58) stimulates its degradation by the Fbw7-SCF ubiquitin ligase. A phosphorylation-specific antibody raised against the c-Myc T58 region to attempt to identify other proteins regulated by the Fbw7 pathway. The first is Ebna1 binding protein 2, a nucleolar protein that, in contrast with a previous report, is likely responsible for the nucleolar staining exhibited by this antibody. The second is Zcchc8, a nuclear protein that is highly phosphorylated in cells treated with nocodazole. Zcchc8 is directly phosphorylated by GSK-3 in vitro and that GSK-3 inhibition prevents Zcchc8 phosphorylation in vivo. Zcchc8 interacts with proteins involved in RNA processing/degradation. Zcchc8 is a GSK-3 substrate with a role in RNA metabolism.