MCCC1 and hepatocellular carcinoma: Here, we report that SIRT4, which is up-regulated by α2δ1-mediated Ca2+ signaling, enhances the production of acetyl-CoA to promote the stemness and invasiveness of HCC by deacetylating MCCC2 at K269, which facilitates the complex formation with MCCC1, and thus enhances its MCCC enzymatic activity.