Fig. 5. Activation of LKB1 does not require T-loop phosphorylation. (A) Amino acid sequence alignment of the T-loop of LKB1 and protein kinases of the AMPK subfamily (Manning et al., 2002). The identical residues are boxed in black and the conserved residues are shaded in grey. The T-loop Thr is indicated with an asterisk. The conserved Leu residue found on AMPK subfamily kinases is marked with an arrow. (B) HEK293 cells were transfected with the indicated constructs and analysis performed as described in the legend to Fig. 1A. Results shown are the mean±s.d. of two independent assays carried out in triplicate.