Figure 1

PKD variants and activity. A) Schematic representation of Drosophila wild type and mutant UAS-PKD variants, PKD-WT, PKD-kd, PKD-SE, dsPKD and human PKD variants, hPKD2 and hPKD3. Apart from dsPKD, all proteins were expressed as GFP fusion proteins. PKD contains a regulatory domain and a kinase domain. The characteristic features include: C1, C2, Zink-fingers 1 and 2; A, acidic domain; PH, pleckstrin homology domain; KD, kinase domain. In addition, hPKD2 contains a proline rich domain (P) at the N-terminal end and a serine rich region between the two zinc fingers (purple box). Two serine residues in the kinase domain (Ser₆₈₉, Ser₇₀₂) are thought to be phosphorylated upon activation of PKD. They were both mutated to glutamic acid in PKD-SE. hPKD2 contains a further possible auto-phosphorylation target within the C-terminus. The presumptive ATP binding site, lysine at the beginning of the kinase domain (K₅₇₂), is highlighted. It was altered to tryptophane in PKD-kd. Numbers refer to codons; they are according to [1] for hPKDs and [13] for Drosophila PKD. B-E) Fidelity and level of expression for the different variants was analyzed in vivo by help of the GFP-tag. Different Gal4-driver lines were used to address tissue specificity of GFP-expression. The examples show specific GFP-expression in the posterior compartment of a wing imaginal disc (right half) as can be achieved by using the en-Gal4 driver line. For better visualization, discs are outlined with dotted lines. The antero-posterior (yellow line) and the dorso-ventral borders (purple line) are indicated in B). Shown are B) wild type PKD (en-Gal4/PKD-WT^10-1), C) PKD-SE (en-Gal4/PKD-SE^112-6), D) PKD-kd (en-Gal4/PKD-kd^102-1) and E) hPKD3 (en-Gal4/hPKD3^X-1). Scale bar, 100 μm.