Figure 3.

USP1 deubiquitylates BCAT2 at the K229 site. (A) K229R mutation decreases the BCAT2 ubiquitylation level in HEK293T cells. (B) USP1 knockdown enhances ubiquitylation of BCAT2^WT but not BCAT2^K229R mutant. (C) USP1 decreases ubiquitylation of BCAT2^WT but not BCAT2^K229R. (D) BCAA deprivation enhances ubiquitylation of BCAT2^WT but not BCAT2^K229R mutant. (E) K229R mutant disrupts the semi-endogenous binding between BCAT2 and USP1. ‘Ratio’, USP1/Flag. (F) K229R mutant significantly attenuates BCAT2 enzyme activity. Mean ± SEM of n = 4 biologically independent experiments, two-tailed t-test. Data in (A–E) are representative of three biologically independent experiments. ^****P < 0.0001.