Smurf1 controls S phase progression and tumorigenesis through Wee1 degradation.

Smad ubiquitination regulatory factor 1 (Smurf1) is a HECT-type E3 ubiquitin ligase that regulates several important signaling pathways, including the bone morphogenetic protein pathway and the transforming growth factor-beta (TGF-β) signaling pathway. However, the function of Smurf1 in cell cycle progression remains unclear. Here, we demonstrate that silencing of Smurf1 results in S phase arrest, confirming that Smurf1 is required for S phase progression. Furthermore, we demonstrate that Smurf1-mediated S phase progression is largely dependent on the ubiquitination-dependent degradation of Wee1. This study defines a novel role for Smurf1 in controlling S phase progression by promoting Wee1 degradation.