Smurf1, also known as SMAD specific E3 ubiquitin protein ligase 1, is a HECT-type E3 ubiquitin ligase. It plays crucial roles in multiple biological pathways, such as the bone morphogenetic protein pathway, non-canonical Wnt pathway, and mitogen-activated protein kinase pathway [7]. It is involved in cell growth, morphogenesis, migration, polarity, and autophagy, and is related to physiological manifestations like age-dependent bone formation deficiency and tumor cell invasion [7]. Genetic models, like Smurf1-knockout mice, have been valuable in studying its functions.

In cancer, overexpression of Smurf1 is linked to poor prognosis in various cancers. For example, in glioblastoma, colon cancer, and clear cell renal cell carcinoma, it acts as a tumor promoter by ubiquitinating and degrading tumor-suppressing proteins [1]. In KRAS-mutated colorectal cancer, Smurf1-mediated PDK1 neddylation is essential for PI3K-Akt signaling and tumorigenesis, and Smurf1 deficiency reduces tumorigenesis in a genetic mouse model [3]. In hepatocellular carcinoma, Smurf1-mediated ubiquitination of UVRAG promotes autophagosome maturation and inhibits tumor growth [2]. In glioblastoma, ER stress induces Smurf1 degradation, and knockdown of Smurf1 leads to cell apoptosis, while overexpression activates NRF2 signaling to protect cells from ER-stress-induced death [4].

In lupus nephritis, SMURF1 upregulation activates the cGAS/STING/IFN-1 signal axis by ubiquitinating YY1, facilitating apoptosis in podocytes, and SMURF1 knockdown inhibits disease progression in vivo [6]. In dry age-related macular degeneration, inhibiting Smurf1 alleviates acute retina injury, and Smurf1 is involved in exacerbating oxidative stress injury and inflammation in the retina [8]. In ameloblasts, Smurf1 regulates cell polarization through ubiquitination-mediated degradation of RhoA, and local knockdown in rat lower incisor ameloblasts results in enamel matrix secretion disorder [5].

In conclusion, Smurf1 is a key regulator in multiple biological processes and disease conditions. Model-based research, especially using Smurf1 KO/CKO mouse models, has revealed its significance in cancer, lupus nephritis, age-related macular degeneration, and tooth development. Understanding Smurf1 provides insights into disease mechanisms and potential therapeutic targets.