The interaction between 14-3-3 and LKB1 is dependent on the
phosphorylation of LKB1 at Ser334. (A). GST-14-3-3ζ bound to
Glutathione Sepharose 4B beads was incubated with the cell lysates of
HEK293 cells treated with DMSO (vehicle control) or 10 μM
Akti-1/2. The endogenous LKB1 associated with GST-14-3-3ζ was
detected by Western blotting using an anti-LKB1 antibody. (B). HEK293
cells overexpressing Flag-tagged wild type LKB1 were treated with or
without 10 μM Akti-1/2, followed by co-immunoprecipitation using
anti-Flag M2 agarose beads. 14-3-3 proteins associated with Flag-tagged
LKB1 were detected by Western blotting using an anti-pan-14-3-3
antibody. (C). HEK293 cells overexpressing wild type LKB1 (WT), S334A,
or S334D were incubated with GST-14-3-3ζ-bound Glutathione
Sepharose 4B beads, and the immunoprecipitated proteins were detected by
Western blotting using an anti-Flag antibody. (D). HEK293 cells
overexpressing wild type LKB1 (WT), S334A or S334D were subjected to
co-immunoprecipitation using anti-Flag M2 agarose beads, and endogenous
14-3-3 proteins associated with Flag-LKB1 were detected by Western
blotting using an anti-pan-14-3-3 antibody. The relative ratios of the
protein bands in Western blotting results were calculated and presented
as the means ± SEM from at least three independent experiments.
* P <0.05 vs corresponding controls.