Figure 1

Comparison of HIPK structures and tyrosine phosphorylation. A, Schematic illustration of HIPK1-4. The definition of the domains in HIPK1-3 was adapted from Kim et al. [26]. Nuclear localisation sequences (NLS) and the tyrosine residue in the activation loop (Y) are indicated. B, The tree illustrates the sequence identity of the catalytic domains of HIPK1-4 and DYRK1A and panel C shows the alignment of the activation loop sequences. Tyrosine residues known to be autophosphorylated in HIPK2 and DYRK1A are highlighted (red) [28,29,34]. D, GFP fusion proteins of HIPK1-4 and DYRK1A were immunoprecipitated from transiently transfected HeLa cells. Tyrosine phosphorylation was analysed by immunoblotting with a phosphotyrosine-specific antibody (pTyr). Total amounts of the recombinant proteins were detected with GFP antibody. The figure is representative of two experiments.