SMARCA4 and cancer: To understand how the Sth1 structural hub regulates DNA translocation, and to determine whether certain cancer-associated missense mutations in BRG1 create gain-of-function nucleosome remodeling activities, we introduced into STH1 25 alanine substitutions, and 11 cancer-associated missense mutations (chosen using the Catalogue of Somatic Mutations in Cancer [COSMIC]) (Tate et al., 2019) (Figures 1B and 1C).