For details, see the Results and Discussion section. N-T, N-terminus; C-T, C-terminus; N-lobe and C-lobe, lobes of catalytic domain. The numbers associated with the disordered regulatory domain denote the relevant amino acid residues (Asp³¹³, Gly³⁴⁰ and Lys³⁷⁶) at the C-termini of FLAG–MST3(Δ314–431), FLAG–MST3(Δ341–431) and FLAG–MST3(Δ377–431) respectively.