Expression, purification, and microscopic characterization of the tumor suppressor KLHL6

Kelch-like protein 6 (KLHL6) plays a critical role in preventing the development and survival of diffuse large B-cell lymphoma (DLBCL) through its involvement in the ubiquitin proteasome system. Specifically, KLHL6 binds to cullin3 (Cul3) and the substrate, facilitating the assembly of the E3 ligase responsible for substrate ubiquitination. It is imperative to investigate the precise function of KLHL6 by conducting a structural analysis of its interaction with Cul3. Here, we present the expression, purification, and characterization of the full-length KLHL6. Our findings demonstrate that the addition of a Sumo-tag significantly enhances the production of KLHL6, while also improving its stability and solubility. Moreover, through gel filtration and negative staining electron microscopy (EM), we observed that KLHL6 adopts a homomultimeric form in solution. Additionally, we found that the presence of Cul3NTD enhances the stability and homogeneity of KLHL6 by forming a complex. Consequently, the successful expression and purification of full-length KLHL6 serve as a foundation for further investigations into the structure and function of the KLHL6/Cullin3/Rbx1 substrate complex, as well as provide a potential strategy for studying other proteins within the KLHL family that possess similar characteristics.