SPOP Promotes Ubiquitination and Degradation of LATS1 to Enhance Kidney Cancer Progression

Background: Emerging evidence has demonstrated that SPOP functions as an oncoprotein in kidney cancer to promote tumorigenesis by ubiquitination-mediated degradation of multiple regulators of cellular proliferation and apoptosis. However, the detailed molecular mechanism underlying the oncogenic role of SPOP in kidney tumorigenesis remains elusive.

Methods: Multiple approaches such as Co-IP, Transfection, RT-PCR, Western blotting, and animal studies were utilized to explore the role of SPOP in kidney cancer.

Findings: Here we identified LATS1, a critical component of the Hippo tumour suppressor pathway, as a novel ubiquitin substrate of SPOP. We found that LATS1 interacted with Cullin3, and depletion of Cullin 3 upregulated the abundance of LATS1 largely via prolonging LATS1 protein half-life. Mechanistically, SPOP specifically interacted with LATS1, and promoted the poly-ubiquitination and subsequent degradation of LATS1 in a degron-dependent manner. As such, over-expression of SPOP promoted cell proliferation partly through regulating cell cycle distribution in kidney cancer cells. Furthermore, SPOP also promoted kidney cancer cell invasion via degrading LATS1.

Interpretation: Our study provides evidence for a novel mechanism of SPOP in kidney cancer progression in part through promoting degradation of the LATS1 tumour suppressor.