Extended Data Fig. 8: SHMT2 blocks the BRISC active site.

a, Analytical size-exclusion chromatography of different forms of SHMT2ΔN, preincubated with BRISC (left) and SDS–PAGE analysis of peak fractions (right). Data are representative of two independent experiments. b, K63-linked diUb (grey) modelled on the MPN⁺ domain of BRCC36 using the AMSH-LP–diUb structure (PDB code 2ZNV) as a guide. The SHMT2 obligate dimer sterically clashes with the modelled proximal ubiquitin. c, Michaelis–Menten (top) and Lineweaver–Burk (bottom) plots for BRISC DUB activity against a K63-linked diUb fluorogenic substrate with addition of SHMT2ΔN(A285T). Technical duplicates are shown and data are representative of two independent experiments. d, Superimposition of SHMT2 dimer and tetramer forms. The SHMT2 obligate dimer from the PLP-bound tetramer structure (PDB code 4PVF, coloured grey) was overlaid on the SHMT2ΔN(A285T) dimer bound to BRISC. The second obligate dimer from the SHMT2–PLP holoenzyme sterically clashes with the BRCC36–Abraxas 2 superdimer. Movement of α6 and α7 helices is indicated. e, Analytical size-exclusion chromatography of SHMT2ΔN dimer and tetramer (+PLP) forms with BRISC (left) and SDS–PAGE analysis of peak fractions (right). Data are representative of two independent experiments.